The resolving power of analog, especially on a well engineered tt with a high end MC and good electronics is pretty incredible really. FAR better than the best redbook CD; it can't even come close. Grand Funk red album for example is almost like the band is in the room, literally. Of course the downside is surface noise, etc. I have an ultrasonic cleaner for that too, but it can only do so much.
And it is first and foremost an engineering quest. Dragging a tiny stone through a vinyl trench basically, trying to resolve motion down into the nanometer range. Then amplify that by ~ 1 million X into the motion of the speaker cones. It's rather amazing that it works at all really. Generally speaking of course.
It's then not hard to see that
any spurious movement in that process is detrimental to extracting the signal; it's quite an engineering challenge. Linn for example understood that well back in the 60's/70's though. And the founder was a proud Scottish mechanical engineer
It's why they use an expensive, extremely tight tolerance single point thrust bearing for example. Also why they use an AC synchronous motor rather than DC servo (it's smoother). And even that improves by synthesizing the drive waveform (ie Lingo PSU).
It's the mechanical equivalent of maintaining signal in electronics. I've found that microvolts matter electrically in audio; it's not trivial to deal with that. Nor is it trivial to deal with nanometer range of movement.
In a DAC design project recently I found that even 10's of ps of CLK pin jitter can/does make an audible difference. Reducing it from ~ 80ps -> less than 2 ps in this case. It takes awhile to digest that and appreciate why/how (as much as one can anyway). It takes a high resolution system to hear it readily of course. A generic PC based audio system for example, it doesn't matter really. But in a high res system even the wires are audible. Resistors can make almost as big a difference as caps. Etc, etc.
To get it > good takes serious effort. You just can't get anywhere near that with the $200 jobbies at Walmart or your local groovy record store.
T