I think many experienced programmers forget how hard it was to write good code in the first place, whatever abstraction they started to use. I "learned" Java

I think many experienced programmers forget how hard it was to write good code in the first place, whatever abstraction they started to use. I "learned" Java and C++ very quickly. I'm sure I was banging out code and stopped looking up most things within weeks. However, it took me years to actually understand how to write good code in those languages. I had to learn the patterns, I had to learn where the short-cuts and sharp edges were. I had to learn what features to avoid and which ones to embrace. It took a long time, but now it's all habit and instinct. I don't even have to think about it. Asking someone to switch to using a new paradigm—like moving from OOP to FP—is asking them to relearn how to structure a program. All those habits and instincts no longer apply and new ones need to be learned. It takes years to learn how to write good high-quality FP programs. I know I'm still learning and I first picked up Haskell as a primary hobby four years ago. It probably took me a year before I really understood what a monad was and could apply that abstraction, similar to how long it took me to really understand and apply things like visitor patterns. I believe that if you took an entirely untrained person you could get them to be at least as productive if you taught them with FP versus OOP from the start.