How to stay afloat in the IT industry?

The business (as always, I guess) is searching for experienced developers. Ideally experienced in specific frameworks (ex. React/Angular(JS)/Vue). But frameworks come and go and you can't necessarily transfer your experience from framework A to the new one B.

So what's the point of learning new frameworks, when tomorrow there will be new ones which will leave you back at square one? It feels to me as if I'm forced to learn the new stuff (good or bad) just because they're in demand.

I've read articles of people who state that developers should know the language basics, programming principles and design patterns. And not dive straight into frameworks unless absolutely necessary. But knowing the core language functionality IS STILL NOT GOOD ENOUGH for the business. What's up with that? Who makes the decision what technology to use?