Too many stuff, DEI hiring is not the only issue
- Poor management that is the standard in the west for decades: "hey guys let's have this ambitious idea, then when we are not screwing up by infights we scrap everything at the mid of the road and we gotta reboot and rush it out to make to the deadline"
- Better graphics demand much more workforce, that's why developers outsource chunks of assets to outsourcing companies, when they are not taking sister studios like Rockstar and Activision did.
- Zero stay culture is the standard in the west: Most of the workers in japanese studios stay for a decade or more, key staff stays almost their whole career in a single studio. In the west I only know Bethesda for doing that with many of the Morrowind staff still working on the company to this day, and Zenimax management was ruining that with their orders of multiple GaaS games in a short time. The root of the issue is a ouroboros where workers doesn't stay because companies doesn't train them, and companies doesn't train them because they're not going to stay, when its not that, I believe is the lack of multiple projects in the studio to keep them on.
- It's the trend of the day, remember that everyone wanted to have their own Gran Turismo at 128-bit generation, then in the HD generation it was with Guitar Hero and FPS.