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

When I was a young man this was an important issue for me.  So much so that it swayed me to buy a Rabco SL-8E arm when that was considered state of the art.  It did lift at the end of play I'll give it that much.  I also bought a Mitsubishi EC-1, which is still kicking I believe.  I gifted it to a starving college student a few years ago.  I'm not sure why or when this feature stopped being important to me.  Probably the CD introduction did it.  When I just want to kick back with music as a back drop like right now, I just pop in a CD.  When serious listening is the priority then needing an automatic arm is not necessary or even desirable quite frankly.

Back in the day I had a Dual 1219 that stacked records and multi record sets were generally set up for stacking.  Record 1 had side a and d, and record 2 had side c and d, for example.  Operas were more complicated.  ;-)  I used the stacking feature at that time, still have all those records.  No harm came to them.  So the assumption that record stacking harms records is not axiomatic.  If I had a lot of old multi-record sets that were configured that way, and had a penchant for listening to them with any frequency, I would not hesitate to acquire and happily use a changer.  Both Dual and Miracord made good ones.  I know because I set up and cared for a lot of them for my happy customers.  With that said I can't imagine that tooling up to manufacture such a product today would pay dividends.