Who uses high end TT setup for vintage records ?

Pani,

But then truly neutral systems should not be biased to any recording technique, it should just bring out whatever is there in the groove "in the right proportion"

A TT system with good resolution will bring out what is in the groove --- only IF the playback is effected correctly.
Which means numerous things -- for example, playback speed!
Differences in the cutting process make older records play better at different playback speeds...

The TT is a mechanical device, so many parametres affect the result, and these parametres may vary with each record, albeit slightly.

I've always considered a good turntable setup to be agnostic in regards to source material vintage.

That is a very good way of putting it!

FWIW, the cutting needles used in cutter heads to make LPs have not changed particularly since the late 1950s.

I am with Audiofeil to make the story short.
Design done right counts and not everything we can buy today will do a real
good job.
Differences in Arm Design, Material, Bearing, Energy Transfer and a proper
Geometry will show you very different listening results, carts are not so critical
overall, some diamond cuts can do a better job than others and this is probably
the reason why you can hear that some sound better with older vinyl.
The older records have sometimes a very high dynamics, mainly from the
middle to the last tracks, some Arms can't track them well, they produce
distortions, not in a way that you can hear it clearly, but the musical flow is
different. VTF is also a chapter, 1.6gr and a soft cantilever will give you total
different results than a Cartridge which was designed for 2.5gr...
Reissues have normally a lower, pale high frequency area, needles which
compensate that can sound very different with Originals( 1960+) ... there are
indeed differences, but there are technical reasons for it.
Btw. I tried a few mono carts and my choice was Lyra Helikon with a modified
Diamond, good tracking, super silent, no hum...there is worse out there... :-)

I am always taken back by the sound those older LP's have hidden in them. I found that better equipment doesn't emphasis those ticks, pops, and noises that lesser equipment seems to bring out, yet does bring out those audiphile traits that make us smile. And too....someone on these posts said that digital LP's are no good....I completely disagree. Some of my best sounding records were done digitally

One nice thing about LPs from the 50s and early 60s is that they have an all-tube recording chain! The better your playback the more you get the benefit of that.

But I've got a lot of good LPs with a digital master tape as well. Most people don't realize that the biggest area of degradation between the digital master and the CD is the process of making the CD itself. If the LP is mastered from the master tape it stands a good chance of being better than the CD.