I haven’t see this personally, I’ve only seen the opposite, companies pushing for full-stack devs. And from what I’ve seen, people self-select frontend vs backend despite teams pushing and hoping for more full-stack activity from every person on the team.
Frontend and backend and ops are specialized activities, and those domains are only getting more specialized and more complicated over time. Writing an API and designing CSS almost couldn’t be more different, and they’re both full time problems.
When I started a company with a friend, we both wanted to be full-stack and we both tried multiple times, but we just automatically drifted to me on the UI and him on the bots. After a while, when I would try to write bot code I would screw it up despite good intentions, strong knowledge of the code, and unit-tests in place. I would forget important security or schema details, or not quite understand the way my partner’s code had changed structurally even when we talked about it for hours. He’d get tired of explaining it and just write the code. Same thing happened the other way when he’d dip his toes in the frontend. If two people who want to be full-stack and communicate non-stop can’t make full-stack happen, I’d guess it’s a hard problem.