Not finding bytecode files is not that big of a deal. While it's a very minor performance loss, it isn't critical to how Python works (and since it looks for bytecode-only files that use-case isn't broken either).

But the real problem is that zipimport is such a nasty chunk of code that no one wants to fix it. Yet more evidence we just need to rewrite the whole module. I created issue #25711 to track a rewrite.