The reason for React’s “draw the rest of the owl” (which is a great way to describe it) mindset is that it’s born not as a framework but as a library, and to this day self-identifies as such. It by design tells you nothing about and is agnostic with respect to how you organise your code, where to put tests, what bundler to use, etc.

IIRC React itself doesn’t even know anything about the Web or DOM, as that integration is supplied by the pluggable reconciler, which lives in a separate library (ReactDOM).

One could argue that with the amount of batteries included perhaps it ought to undergo a grand status change, but until then it’s hard to blame on the authors of a library that they are not delivering a framework.