Perhaps he feels the others as well. Nothing wrong with any of 'em. I read his letter somewhat differently. They ain't no sech animal. So, any system competes with all others for your investment, whether cash changes hands or not.
Perception is reality.
If they are distinct, they compete. I'm sorry to have to disagree with Linus Torvalds, but it does matter what people call Linux, and this is why. That's my two pfennigs, anyway. Hope you enjoyed it. I know Perl's Tk400.200 extension compiles on most major Linux distributions, and I am fairly certain the OpenGL module does as well.