Here is Tim O'Reilly's [link|http://www.oreillynet.com/pub/a/network/2002/06/28/vendor.html|latest column].
Note how he emphasizes that the entire open source dynamic is driving off of the grass-roots. We neither need nor in many cases do we want vendors to be driving most of development. Depending on the project or platform there may or may not be a profitable role for vendors. Where there is, the fact that they can externalize a lot of their development costs will be key to profitability.
The flip side of that is that if you take development out of end user's hands, the dynamic is ruined, and there won't be any successful vendor models.
Cheers,
Ben