>"most “full stack” developers have not truly mastered front end and back end" We need to do something about the default of developer bashing prevalent in our culture. There's no true Scotsman, nobody is 100% perfectly attuned to the latest developments on any surface. Instead engineers develop along competencies that are required in their work. If you need to deep dive into a backend problem, you'll get better at th…
What I do know is that there are many dishonest types that will say they are "full stack" when they really aren't. Then there are others that will not lie on a resume and say they are, when they in fact aren't.
The reality is that any dev can learn to do both - but hiring managers want it all, now, for free, and with a smile.
All that said - the more disciplines and domains you use day to day, the worse off you are going to be IMO. Sure it's good be a polyglot, but specializing helps to hone and sharpen skills.