Incidentally, it is possible to edit piano rolls prior to release (lots of popular music one's were) to add notes, remove wrong notes, etc. Not sure if Rachmaninov ever needed, or was tempted, to do that.
sounds like that would be a fun toy for a short period of time
Living where you do, you will have heard a Duo-Art push-up belonging to Denis Condon, and created by him and Peter Phillips, who was over here visiting a couple of weeks ago. That was back in the 1980s.