I'd argue there are too many incompatibilities between minor and major version changes between the "core" react libraries (DOM, react-router, etc) and those teams were a bit reckless with the API surfaces and how they fit together.

At the end of the day it's free software and it's not like I've been submitting PRs to improve it. Further react-router is something you can setup at the beginning of a project and largely never touch again. Its not the end of the world, but it does cut a lot of folks who are new to React, Frontend, etc., and contributes meaningful costs to frontend development as a whole.