Why hasnt a turntable manufacturer produced a table with automatic tonearm return/shutoff?

I don’t see any impediment to engineering a high quality table with automatic or semi automatic features.  Perhaps such tables are out there, but they are not recognized as high end.  That suggests that the “reason” has to do with us—the consumers.  If there were demand for high end tables with such features, manufacturers would build them.  But, it is the buyers who baulk at paying a lot for such tables because the buyer perceives such features to not be consistent with high end.  
Another issue would be compatibility with different tonearms.  Ideally, such features have to be integrated with both arm and table, so they would not be popular with high end buyers who want to choose arms and tables separately.

Nothing gets the heart rate up like hearing the same record play when you have stacked records on top.  That means a new record did not drop and is probably barely hanging on waiting to sandwich the cartridge between the two records.  When a record does drop properly there is no scratching or rubbing between the grooved part of the record because they don’t touch; there is a raised bead on the edge of the record and the center of the record is thicker than the playing surface.  However, the spindle hole does become larger over time because the record spins while the spindle is fixed so the rubbing slowly reams out the hole.