Then maybe you also missed mine...
Other than the fact that a single OS to rule them all is a BAD idea all around from an end-user perspective, you seem to be coming at the problem backwards.
I never said it was a
good one, just that it'd make the whole "omni-platform" thing a hell of a lot simpler. I'm speaking in purely technical terms,
I do not think this is a thing people should actually do.
OpenGL runs on damn near anything, I haven't run across a distro that isn't capable of supporting it at least and I've been distro surfing for a while now, so your statement as posted is actually incorrect as well as looking at the wrong end. The tools such as OpenGL, Qt, and other open-source resources are platform-independent by their very nature. So yes, you CAN actually create platform-independent programs. It's only when you get into abusive corporate intellectual property pissing matches that you get platform-dependent crap.
That's not how it works, dude. Every platform has its own ways of interacting with certain resources: RAM, storage media, and so on. When designing things for it, even an abstraction layer like the Qt framework, you have to write actual code to interface
with that given platform. That increases the size of the abstraction layer and increases the amount of time spent developing said layer. This is where open-source things come in handy, since you can have a diverse group working on a multitude of platforms creating APIs and whatnot to integrate with their specific platform. It has little to do with licenses. Unless we're talking about Apple.
Furthermore, because resources like these are both open-source (and thus free to distribute, and so can be used as dependencies without forcing the end-user to pay out the ying in licensing fees), any developer of an operating system can simply build their OS to incorporate them from the ground-level up so that the point is entirely moot. You *CAN* have platform independent resources, and thus games based on said resources, and thus games which are themselves platform independent. You just have to avoid BS licensed code.
You seem to have a massive chip on your shoulder when it comes to licenses and licensed code. I...do not understand this. The GPL is, as the name itself states, a license. Almost all code, nowadays, is licensed in some way, shape, or form. Its just that some licenses are more limiting than others. Honestly, I don't mind commercial licenses that aren't uber-restrictive. At the end of the day, people
need to make money. Some of them, like me, make money being software developers. In the words of that annoying Rally's ad: "You gotta eat."