It's not convergent evolution when people are copying, but copying doesn't obviate emerging aesthetics. Once upon a time, websites did not all have menu bars across the top, is this a result of despicable copying, or of lots of people simply deciding it was a good idea? Whether or not I think a given UX trope is useful is irrelevant to others choosing so.
My assertion is quantity-neutral. I simply don't think it matters how much is copied, just the fact that any copying is going on at all signals that the look and functionality is having an influence.