You still haven't given any examples that you've actually come across. All criticism is valid, but you should at least give some shred of evidence. Lots of things work badly (or sometimes just differently), but icons or 'app stores' are not on that list. An icon not showing up is always the fault of the application, or because you've previously been messing with files you shouldn't have been messing with. Again, using nothing but the visual interface, none of this would happen.

Ironically, the second search result I got was about some icons for a certain application not showing up on Windows, another was for Spotify on Windows showing a wrong icon, and pretty much all other results were about desktop icons not showing up (which is something else entirely) or about a broken icon theme (which is also something else entirely).