Any of the various drive systems..belt, direct drive, and idler can work well is designed correctly and executed correctly with excellent isolation and resonance control. Main reason belt drive tables have proved so popular with high end is, in my thoughts, that the cost of entry to the belt drive high end market is much less than the cost of entry into the high end direct drive or idler wheel market.
Imagine how much money Panasonic (owned Technics Radio and Broadcasting Division which produced such gems as the sp10, epa100/500, and a few other very neat things) put into R/D and and then plant and equipment to produce such a fine machine; ditto for the Kenwood L07D or the top Denon professional units. Pioneer also made some cost no object direct drives, too.
Now, I like my Scheu Premier and the Acoustic Signature was an alternate and I went with the Scheu for the dual arm plinth for a modest uplift. I am under no illusion that this is simply a well designed table made out of acrylic. The bearing is fairly straightforward to manufacture once the design is finalized; that does not take millions of bucks to devlop...same with the acrylic platter and plinth and armboards. The motor is sourced from Maxxon and some electronics work is done by Scheu. This is not terribly complicated from an engineering and manufacturing perspective.
Now try to envision the plant and equipment and start up costs for the old SP10 and the SL1200 and its legion of variants. Who can afford to do that anymore with such a small market?
That is the reason we no longer have high quality direct drive and idler wheel turntables; manufacturing costs do not support production to such a small market.
Belt drive is the least expensive way to get good performance and the inherent limitations of belt drive are tackled by other solutions. Some use mass; some like DPS use other techniques to arrive at the same destination.
