Sounds like the "unsustainable" part is having leadership that only knows Candy Crush, Clash of Clans, and Call of Duty exist and demands every franchise produce mega-success and endless ongoing revenue.
Company makes stong profits proceeds to lay off people. This is just the unfortunate cycle in game dev. Looking at the names of the studios, they make some games I love but they also look to be in sequel mode with several having future franchise sequels TBD. It sucks, but what it really highlights is not the sustainability of FF7 projects but a wholesale inability to project manage that is endemic in game development specifically and software delivery in general.
