Why will no other turntable beat the EMT 927?

Peter,
I tested the R 80 with the Timeline. The table is about 60 cm away from the wall where the red point is keeping in a stable position. My motor management is controlled by the Dusch Multiconverter DU 937 which allows a felt brake compensation and vari-speed.

I suspect you are talking about speed accuracy relative to the desired rpms, but what about the drag of the stylus in the vinyl groove?

It is possible to distinguish "constancy" (rotation at a constant angular velocity) from "accuracy" (rotation at precisely 33.33 rpm) with a Timeline, altho I am no devotee of the Timeline. But it would be a pain in the ass to do so. One simply needs to make markings at regular intervals on the wall being used to observe the laser beam. If the "dot" moves at precisely regular distances in one direction or the other, with each rotation of the platter, then the speed of the table is constant but not accurate (see above for definitions). IMO, constancy is much more important than precise accuracy, as long as one does not perceive pitch distortion. Tbg, Ideally this would be done with stylus down, playing an LP, to account for stylus drag.

I am just not anal enough to do it, I guess.

Lewm, as I understand it, idler-wheel turntables is withstanding the slow ups of dynamic passages. So the EMT has that going for it. But the mass of the platter also helps greatly thanks to inertia. Also the friction of the idler-wheel is important as is its diameter constancy and the trueness of the surface on which the idler-wheel drives.

I once had a Final Audio tt which was solid copper! The platter weighed 285 pounds which is good, of course, but it was string driven with a knot on the string.

I think all of this means that what we hear is what is chiefly important.

Tbg, Without a doubt, by external inspection the EMT 927 is built like a tank in all respects and to a quality level that far exceeds the visuals of a Garrard or Lenco. The question is only whether all that machinery also results in "the best" sound. And that can be debated forever, as seen here.