[tsimionescu]

Their competitive advantage compared to whom, Windows? Their competitive advantage compared to other Linux distros or to the BSDs is enterprise support, not being open source (all of them are). Apple doesn't even sell their OS at all. So who are you comparing RH to?

[Tepix]

Yes, the competitive advantage when compared to non-open source operating systems.

If they stop publishing non-GPL source code, they have a distinct disadvantage when compared to open source alternatives.