Unfortunately, that's the real world that we live in. It is accepted that all browsers have to, in some way, support the broken rendering that is inherent in Internet Explorer, but greater use of non-IE browsers by money laden web surfers are forcing some websites to change their format so as to be more standard. This is actually a good example because, like VLC, Safari is meant to "playback" web content, not edit or create it. Playback is easy because you don't have to be concerned about how one type of coding on one page might be inadvertently affected by the coding on another page, because you're not using Safari to mix 'em together.
People view QuickTime Player as a "player" application just because on the surface that's what it seems like it is. Heck, it's even got Player in the name! But it also has QuickTime in the name which informs that this is a Player of QuickTime. QuickTime, however, goes much further and deeper than that. Because of QuickTime, when you write an application for OSX, it has the capability to create video, even if it's not a "video" app (PowerPoint on the Mac can create QuickTime video. On the PC, it can't even create .AVI's) The application also has access to all these file types:
http://docs.info.apple.com/article.html?artnum=42617
And they're handled, for the most part, seamlessly.
So, the choice is a robust way of dealing with any type of standard media and ease in converting, say even a set of .bmp's to a movie for the iPod in H.264 format OR the ability to view non-standard media (which is, on the whole, questionably legal in the first place).
The reason why much of the brilliant software for the Mac works is due mainly to a solid, standard QuickTime foundation, do you want to give THAT up?