Vinyl is measurably worse than CD in most departments - noise, distortion , crosstalk, linearity, speed stability, all verifiably worse - a good LP at best will have a dynamic range of maybe 70db, a half speed master maybe a touch better but still under 13 bits and that only till you get towards the label when tracking issues become more serious.
As for the brick-wall filter - there is genuinely (and I have researched this extensively) no credible evidence that frequencies above 20K have any material impact on perception of sound ( TERUO MURAOKA, YOSHlHlKO YAMADA, AND MASAMI YAMAZAKI 1978, and others) . One study (Oohashi) appeared to provide evidence but it turned out to be IMD from the drivers used (Ashihara) .
This is also an interesting explanation of the physics of LP playback
...so you are saying that when you go to the music hall and listen a live classical music all the harmonics are axed @20k exactly. Maybe most of the people don't hear above 16k but that doesn't mean that music isn't there and by applying that filter let's say a Stradivari is no longer, because it is missing it's harmonic signature...
...and to all of you who like to measure, how many of you have let's say a $3000 analog deck + $1500 cartridge and $3000 CD player and can play J.M. Jarre's Oxygene on both sources just for fun of comparing?
...I do :)