[ehtd]

My belief is that a 10x programmer is one that codes for fun and because of that, has tackled a lot of different problems.

Problems solved for "fun" are very different from day job problems, but they often provide knowledge that can be applied.

It the extra knowledge what makes them great.

[dangerlibrary]

That is not incompatible with the point made in the article.

It is also a much stronger claim. Your claim is that the ONLY way to acquire the wide range skills is to program for fun. Such a strong claim generally requires greater justification, which you haven't provided.