Probably because there's a lot of codebases out there that use react that are in a pretty bad state - that are a few versions behind and can't be updated easily due to breaking changes, have a mix of various old and new libraries and patterns for doing similar things, that don't use typescript, or that do but use `any` everywhere. It's a great ecosystem but it's evolved so much and there's my so much variety of ways to do things that it takes a lot of discipline to keep your codebase in good shape if your team is over a certain size.