I believe you can be fairly experienced and realize there are many parts of the language and its ecosystem that you don't completely understand. For instance in

I believe you can be fairly experienced and realize there are many parts of the language and its ecosystem that you don't completely understand. For instance in Scala, I've never written any macro or used something like Shapeless in depth. Spring is a good example too. I used it quite a bit in my junior years and felt like I would never come to master a framework that is so broad (and that felt over-engineered). This doesn't mean you cannot be productive using a subset of the language. There's a balance in what you should allow in a codebase being maintained by a team of varied skillset. Maybe Haskell is on the extreme end here, but the other way (like Python, JS, Go) is even worse in my opinion.