Hard to find? How about the wast majority of apps don't use react or angular. Seriously, let's get out of the echo chamber that is HN.
There are learning curves, inner platform effect (have to do the framework way of doing things), major breaking changes and outdated information, opinionated authors you may not agree with, huge dependencies for users to download, performance bottlenecks and gotchas arising from not using the framework properly or even the framework itself is slow. These things are basically guaranteed.