I think there is some truth in that thought. If they spend some of their energy into learning a backend technology, this would be much better spent effort. From

I think there is some truth in that thought. If they spend some of their energy into learning a backend technology, this would be much better spent effort. From my experience frontend-only developers are often very limited in their programming skills. Frontend development has its own complicated challenges, but usually the programming part is quite trivial compared to backend. And a lot of logic inside frontends would be better off in the backend (Full Stack developer speaking here).