And perhaps those same developers would have a similar opinion of someone who keeps reinventing the wheel?

I am sure they likely do, which only suggests developers' opinions of stylistic qualities and tool choice is an extraordinarily weak metric of competence. A better and more objective metric is an evaluation of the product: the speed of code writing, execution speed, fewer dependencies, few lines of code, and so forth. From that you can guess an opinion that better software is written by better developers. Asking developers to rate each other, or themselves, is next to worthless.

Also - some people are really, really strong in a specific paradigm - say Java + back-end, but have no other skills really.

But then - in their context, they wouldn't see knowing other languages as meaningful.

So it really depends on a whole lot of context.