I know all of the above.
Unlike the CD, which is a unified thing ( with departure from dead neutral either way really small ), analogue record can be soooo multifaceted thing it is mind boggling. And, ultimately, it boils down to record wear. The biggest derstroyer that is quite well hidden is - inertia of all conventional tonearms. Inertia is the least well understood term in nall of analogue audio. The only man that got it right was the late David Gammon of Transcriptors. He is the only one to define what he termed the seesaw frequency. And that is the frequency at which a tonearm oscilates when set for zero vertical tracing force, when it is an equilibrium.
Any normal length - say 9 inch, as the most common - oscilates REALLY SLOW - say 1 Hz or so. That is hopelessly inadequate if it wants to provide the essential function - to present a firm yet stable platform WITHOUT FLUCTUATING vertical tracking force to the stylus. David Gammon set the most important criterion for analogue record playback :
The seesaw frequency should, in theory, exceed 20000 Hz. Since that is impossible, it should - at the very least - exceed the fundamental mass/compliance resonance ( those (in)famous around 10 Hz ).
This is the reason behind his revolutionary Vestigal tonearm. And, in practice it can only be achieved by the lightest of phono cartridges - below 3 gram mass class, This can go as far as requiring plastic bolts and nuts hardware to mount the cartridge. That also means a very high compliance cartridge, if it should have the main mass/compliance resonance at 10 Hz and not too much higher. Of the cartridges available today, that means Ortofon OM (Super) series - but there were others, both MM and MC types, that had suitable specs.
Please check again the Fig.28 of
http://www.theanalogdept.com/images/spp6_pics/TT_Design/MechanicalResonances.pdf - and it should be clear just about what it is all about above. Arm 1 is Vestigal - but, at that time, no cartridges of below 3 gram class were yet available. The results would have been otherwise much better still.
Vestigal was/is a strange mix - work of genious, work of art, testimony to the sloppiness of real human beings ( there were excessive variations of the quality of bearing adjustments ) - and is unlike most other tonearms ever made commercially available in actual daily use. A more robust, "humane", if somewhat downgraded and upgraded at the same time , version is the Dynavector arm - at a MUCH higher price.
All tonearms with as low effective length in vertical direction as Vestigal, and, to a lower extent, the Dynavector arm, suffer from warped records. There is no other way but to change vertical tracking angle when transversing warps - and that not only has as a consequence increase in distortion and decrease of channel separation, but also means change in the appearent pitch of the reproduction. When going up the warp, the pitch lowers - only to go higher than nominal on the downside stroke. And, that is anything but desired.
When I first encountered the Versa Dynamics turntable, all that I could utter was : " ... finally - a well made Vestigal ! " Versa is a SYSTEM - an integrated turntable and linear tracking tonearm , both operating with air bearings. The most important feature : vacuum hold down for the record. It has inbuilt logic which would never allow the platter to start spinning unless the proper vacuum hold down for the record has been achieved.
It is unfair to all those who have never heard a Versa table ( any model, of course the higher up the range, the better, but in principle all of them are the same, only execution is ever better ) with, at a first glance, FAR too low quality cartridge for a behemoth price TT - Ortofon OM 20 Super. Yet, properly aligned and with lowest mass Versa "headshelkl" and without Ortofon additional weight ( cartridge mass in this case 2.3 gram ), this combination FINALLY does achieve the seesaw criterion - the oscillation of the arm set to zero tracking force is in vertical direction finally higher - by the tiniest of margins - than the mass/compliance resonant frequency.
What does it mean - really ? It means that the record can be - FINALLY - reproduced without/SIGNIFICANTLY reduced vertical modulation from the record warps. You can get fooled the signal is not coming off the record, but from a signal generator ... THAT MUCH better. No other analogue record player can pull this trick. I sincerely doubt any other player, be it analogue or digital, can play at this level; Callas was simply unbelievable - as was pretty much everything we threw at it.
It also means this player has the lowest vertical tracking force variations and hence lowest record wear. Of course, one can use better cartridge/stylus - as long it is lower in mass than 3 grams and has high enough compliance. That leaves an extremely small selection of almost exclusively vintage carts - the best of them all probably being Bang & Olufsen MMC1 . Never heard one, let alone on Versa.
Regarding stylus and vinyl groove interface - another , most important factor, but the one most manufacturers of phono playback equipment tend to "conviniently" "forget" to tell you about. The pressure at the actual contacts ( there are two, for left and right channel ) is enormously high - and actually almost liquify the vinyl immediately after the stylus passes that portion of the groove. The catch is to use the pressure that does not result in plastic deformation ( permanent damage to the groove, normally affecting the high frequencies at first ), but stays within elastic deformation of the vinyl. Shure has once termed that Indentation Factor, back in the day, Van den Hul did specify the maximum VTF that is still safe with his VdH I and VdH II profiles - the mention of both by both companies dissapeared in thin airover years. Shure allowed its phono detriorate to the point it was necessary to put it out of its misery some two moths or so ago for good - the "niceties" like Indentation Factor swept under the rug and forgotten long before that. VdH does produce cartridge(s) that can operate at low enough VTF in order to stay well within the elastic deformation of the vinyl - but they are a minority and they cost an arm and a leg.
So... WHAT is the safe figure ? Less than 1 gram for elliptical ( does not exist today, at least not in current production ) , about 1.4 gram for VdH/Paratrace/ Micro Linear/SAS, slightly more for Shibata ( there are two Shibata profiles, differing in contact area ).
Now... how many styli with safe vinyl deformation mounted in less than three gram mass cartridges mounted in Versa table tracked at safe vertical tracking force is out there ? Probably, something closely approaching - zero. Sad, but true.
I can get very close to/meet the above requirement - Transcriptors Vestigal, Ortofon OM40 Super ( FG II stylus = for all practical purposes VdH II ) tracked at 1.4 gram - on a vacuum hold down turntable. This combination has the possibility to be "relatively widespread" - compared to Versa ( $$$, now more than new ) - but the number of serviceable Vestigals is slowly but securely sinking. An even rarer than both Vestigal and Versa that does allow for the requirements ( but without vacuum hold down ) is Transcriptors Transcriber - and one relatively widespread is the ReVox turntable, equally without the vacuum hold down. And at the low(er) end of the price spectrum, there was Aura turntable/arm from Czech(oslovakia?) Republic - an astonishingly good performer, regardless of price.
Bearing in mind with which "atrocities" some, if not most , analogue record users (ab)use their records, I am not surprised at your friend intentionally limitting HF for the commercoially released records. I still have a couple of used test records I brought from Benz Micro Switzerland - to some of them there are still attached the Bruel & Kjaer printouts of their frequency response, made with the reference phono cartridge - both as new record and after a certain number of plays. And the treble does go up in level above certain frequency - as does the distortion.
Shure even documented increase in noise level after certain number of plays of the vinyl record.
ALL of the above detrimental effects regarding record use can be - significantly - reduced with wet playback ; almost forgotten art, that is and will be gaining some traction now ultrasonic record cleaners have come down in price enough for serious record users to consider them in large enough extent. Can be as low as 185 EUR+ shipping.
What was written above is a primer how things should have been done under the ideal conditions. And, it IS perfectly possible. However, we do not live in an ideal world.
With all that said and done - high resolution digital, be it PCM or DSD, does not have the wear problems of analogue records.
No, I have not forgotten any (almost any? ) of what you have told me. Both records ( regardless how imperfect they are ) and HR exceed RBCD in one important area RBCD can do anything about - frequency response, or if you prefer it that way, time domain.