Understanding the differences is only important if you're hopping jobs to a different tech stack though. Which is why the 'following the market' reason is mostl

Understanding the differences is only important if you're hopping jobs to a different tech stack though. Which is why the 'following the market' reason is mostly bullshit if you live in a good city and didn't pick something originally that's gone the way of the dodo. You may open yourself up to more opportunities by being familiar with multiple front-end frameworks, but you're going to be a worse fit for a lot of them, because if my stack is React and Django, why on earth would I hire a veteran React dev that has spent 3 months learning some Vue instead of some Django? Or AWS? Or anything else that I could possibly have in my stack. You're basically resigning yourself to hitting only one checkbox, when there's other candidates out there that can hit more. The big front-end frameworks are far from the most egregious examples too. You raised a great point about people not learning enough to be effective. I'm a big fan of React, but it's ecosystem has a massive problem with this. People are so dependency crazed that every single dev has experience with 10 out of the 200 commonly used dependencies and it's always a different 10 to whatever is being used on the project. Most team's solution to this is to crank their package.json up to 100 dependencies so everyone can feel at home, and everyone goes on these fucking odysseys of superficially learning a ludicrous amount of APIs other people have written without ever producing anything meaningful themselves.