This is becoming less true than it once was. React has been ‘this month’s JS framework’ for 10 years now.

Anecdotally React was not in serious contention (for corporate use) until about 2016 or 2017.

And React itself has not remained a stable API (rise and fall of hooks).

As a sibling mentioned, this isn't really true in the JS space anymore. The JS frameworks and react/vue have pretty much won, so now you one of those UI kits and whatever build system/ancillary tooling your framework says you use. There might be churn under the covers, but the framework abstracts that away for you (though occasional migration issues are bound to come up with big changes).

it's always quiet before a storm :) It'll be fun to fast forward five years and see whether there wasn't some big disruptive change and everyone is now using rust++ for client dev or something? :D