> The general advice here seems to be “learn X while young”

I generalised your statement for you. When people learn anything in their youth, they tend to think of it as "better | easier | True".

It's true for the things we call culture, language, religion, and relatively simple phenomena such as cuisine and programming languages.

We form a personal canon from the first cognitive imprint. It is hard for people to change even when confronted with bias. The programming community is no exception.*

* pun intended