> I think where we disagree is that I don't think of the lower level API as being much of a lock in.
Lock-in here doesn't mean they have no technical means of implementing other graphics backends, it means that implementation is hard.
A lot of common middleware supports Linux just fine. It's graphics that's usually the biggest hurdle. People have expertise to address it, but it's still a tax to pay. And different distros support is a very minor thing in comparison.
If graphics is not the biggest issue, what is then in your opinion?