I mostly agree, with the caveat that people can usually learn something analogous to what the know quickly, but not necessarily in a new domain. E.g. easy to go

I mostly agree, with the caveat that people can usually learn something analogous to what the know quickly, but not necessarily in a new domain. E.g. easy to go from Django to Rails or vice-versa. Similarly, not too hard to go from C++ to Java or Go, etc. But I had a tough time doing front-end development for the first time despite being a pretty strong backend/systems/embedded programmer because the programming model was so different from what I was used to and I was coming into a complicated product.