What I'm actually saying is a bit more subtle. There are types of developers who are very limited in what they can do. They learn some basic "tricks" in the fo

What I'm actually saying is a bit more subtle. There are types of developers who are very limited in what they can do. They learn some basic "tricks" in the form of "If write this magic spell, I get this magic result". These are the mediocre developers. They tend to pick some popular tool and try to market themselves as "an X developer" where X is something that's popular right now. Then there are developers who can create magic. They can build something almost from scratch without having to have a library that already does it for them. These developers can pick up X or Y or Z in a week or two and then they will become 20x more productive with it than the mediocre developers are. I'm not saying it's a bad thing to pick up a tool to market yourself as an "X developer". I'm just saying there's a lot more mediocre people in the pool of "X developer", and if that's what you go looking for, you'll get mostly mediocre people.