Once upon a time there was a solo Linux vendor named Red Hat. Then, it did not have much competition. SuSE was small. Ubuntu was non-existent. Then came Novell and Canonical.
Novell changed the definition of "Linux Enterprise Product" and Canonical slapped all who said "Linux is not yet ready for Desktop".
In the early days, there was no problem because Red Hat served upstream and could not live without this "Community Users". These users were invaluable testers and bug triagers.
But things have changed now. Now, it is a TTM game. Every vendor, that finds a bug or a fix, preferably wants to keep it a secret until its release. All vendors effectively maintain forks and carry them for the entire lifecycle.
There does not seem to be a "Community".
There's also the war of "I be the upstream for everything I ship in my product". So, if you are not the upstream of something you ship, drop it, fork it, re-label it, re-invent it and then re-ship it.
It will be interesting to see how well and how long can the GNU/Lnux Community Model sustain going forward.