While it's clear that most recent innovations from Shimano start with their mountain bike group sets these days, electronic shifting seems to be "a roadie thing" for some odd reason. XTR Di2 exists, but I personally don't see many bikes with it.

Perhaps one reason is that mountain bikers often adopt a 1x setup and thus can't justify the price difference to just shift the rear mech? As a roadie with a 2x Ultegra Di2 setup, the Di2 "synchro shift mode" is lovely and a HUGE advantage (to me) over mechanical group sets. I always hated shifting a mechanical group set from the large to small chain ring (and vice-versa) because of the huge jump in gear ratios and a lot of fiddling around. Di2 solves that problem so I can just focus on riding and not shifting.