Why do turntables sound different?

Right. This is a very scientific approach - let the others do the job and steal the design. Some would argue, though, that the one closest to tape sound would be the one to copy. Continuum, I don't know, I heard that that's Technics not Walker.

By selecting a "thick" oil viscosity a high friction ( relatively speaking ) , quiet bearing is not only possible, it is commonplace. The usual thinking behind this design is that the bearing is more speed stable, which it is not . So, accepting that the logical extension is to build a bearing with the least friction as possible for the reasons noted above. The lowest friction bearings are air bearings, but the cost is complexity and potential pump noise.

 
inna OP
Right. This is a very scientific approach - let the others do the job and steal the design. Some would argue, though, that the one closest to tape sound would be the one to copy. Continuum, I don't know, I heard that that's Technics not Walker.

Whoa! What? Yo, check it out! Technics? What the ding dong?! 

@has2be 

"Do you actually suggest that higher friction in a turntable bearing won’t create and amplify vibrations ..."

Got it in one. Almost. I repeat, "The two may not be the same."  I also repeat, "Energy can be dissipated by heat (microscopic motion) as well as by sound (macroscopic motion)."

You say, "... which is odd since reducing those energies from even being seems to be more a desire than fixing or ignoring its correlation." Do you mean, "it is desirable to prevent those energies from arising, rather than fixing them"? Is that what you were trying to say?

If so, then I agree with that. I use air bearings and mag lev myself. But that is irrelevant to the point of how all bearings must function.

You have made categorical statements about how all bearings work: that macroscopic noise is a monotonic function of friction. I don't think so, and it's going to take more than an a priori argument to convince me - this is a matter of physics, not metaphysics.

has2be, In some instances, the design calls for a lubricant that per se creates some drag on rotation of the platter, so the motor has constant small resistance to work against.  This can be devised to improve speed stability. Best example I can think of are the Garrard 301 grease-bearing types.  Friction thus created does not produce noise.  It can also be done magnetically, in some other cases, but you might fairly argue that magnetic drag is not a kind of friction.