Direct Drive vs. Idler Drive vs. Belt drive

This discussion hasn't "boiled down" to anything at all.  The subject at hand is always a function of who feels like posting at any given time of day or night.  My personal predilections are against excess complexity per se.  I don't want a compressor in my room OR in the next room OR in my system anywhere, not because an air bearing is not excellent but because I don't  want the complexity, the hoses, the moisture problems, the filters, etc.  And probably also because the turntables that employ air bearings are beyond my upper limits in what I am willing to spend.  There IS a point where cost is laughably high.

Even with magnetic levitation designs, there are quite different approaches.  The ClearAudio and Verdier, etc., designs float the platter, with a shaft only used to center the platter. 

Some designs use magnetic levitation to reduce the load on a conventional bearing.  This load reduction reduces wear and reduces the amount of noise generated by the bearing itself.  Hard contact, in this design,  is not designed to just prevent vertical movement, it is used to allow dissipation of any vibration imparted in the platter by the stylus tracking the grooves of the record.  The bearing itself is part of the path for dissipating this energy.

The old and refuted Aristotelian methodology discriminated between
''essential'' and ''accidental'' properties of objects. His physics  is
refuted by Galileo his logic by Frege.
Those who are not familiar with modern methodology still use 
Aristotelian ''essentialist philosophy''. Think about ''essential 
part'' by MC carts being the stylus and its shape. The kinds of
''drive'' by TT's etc.,  etc., etc. 

Addendum. Some examples can illustrate some ''state of
affairs''. Say the question why Russians think that Hegel is
the most important philosopher? Because of his (dialectic)
Logic? Well he wrote an big book (in two parts) with more
than 1000 pages with the title '' The science of logic'' in
which there is no on single sentence relevant for modern
logic. 
 

What has Hegel and Aristoteles to do with our forum?
We have seen Aristoteles  ''essential properties'' but need
to add Hegels ''logical invention'' called ''the unity of the
contradictory''.
According to chakster  the micro ridge stylus is ''essential''
while our eloquent member from Australia was so impressed
with his Sony XL 88 D that he declared the precious  to be the
best ever (in his) collection. He ascribed this ''quality'' to the 
(diamond) cantilever but the case is that this cart has  elliptical
 stylus. Aluminum cantilevers? Are you joking ? Never heard about 
beryllium or ,at least, boron or ruby cantilevers ? But the same
person ''confessed'' that among his darlings belong FR-7 fz as
well Takeda's Miyabi. Both with aluminum cantilevers. 
Such, according to modern logic inconsistent statements, can be
found in nearly each thread. That is the ''connection''. 
 
.