Not very long, I'm afraid. I am mystified at the high percentage of Linux users who have no concern at all about the inclusion of proprietary binarys in default Linux distributions. Linux has moved to the very verge of mainstream acceptance without these inclusions in a very short time, and suddenly people decide it can't take the final step without changing what has worked so well to date.
The real issue is that an entirely free (libre) OS can not be brought under corporate control, and therefore can not be dependable as a revenue source. Hopefully, a large enough base of users will see the truth of the matter to maintain a viable "real" Linux environment, but with people like ESR and Linus Torvalds jumping on the corporate bandwagon, there are major challenges ahead.
Here's another recent LXer link
that addresses a completely different facet of the same problem.