Half the cost of the game is marketing. And marketing is an effort that builds upon itself
The more smaller games you have, the more you have to market to niches from scratch. And niches are generally more inclined to be informed users. And it takes a developer with vision to make a satisfying niche hit. Well it always takes vision but…
Meanwhile one big bombastic game will get a bunch of mainstream folks hyped over qualifiers of scope instead of quality. Yes, I am saying hype culture is primarily an idiot’s hobby, but idiots still got cash.
Plus, plus, most studios don’t really see their junior devs as something worth fostering. Better off burning them out and replacing them.