How do people who consider themselves as problem solver fair in the industry?

Earlier in my career I had heard that there are people in tech industry who aren't restricted to one technology and they will produce the best product irrespective of tech stack.

And they won't have any problems switching to a different stack to solve the issue or achieve their target.

Now every job requires a specific year of exp in 1 or 2 tech stacks. But the people I'm talking about are generalist.

Is there still a demand for these guys?