The linux trademark situation is indeed instructive. The Linux marks are owned by an individual and the licensing is managed by a non-profit foundation....not by a for-profit entity.
I am not saying that the dominate for-profit vendor needs to own the mark to do business. If I am saying anything, I am saying that is exactly the situation which upstream projects should endeavor to avoid if they want a robust multi-vendor support network. They need to try to make it possible for multiple vendors to use the marks on a non-discriminatory basis in conjunction with commercial products and services.
What I am saying is that making sure that _one_ vendor (or group of vendors) does not have undue influence over how the marks are licensed to other contributing vendors in order to ensure a fair playing field with regard to marketing products that make use of the upstream code.
So to go backing to the specifics of your analogy with regard to the linux marks and Red Hat....
I would _loath_ it if Red Hat owned the marks to the linux kernel and set up a trademark policy which gave themselves the preferential and discriminatory access to use the marks in their marketing materials over competing vendors who wanted to use the linux marks in association with their products and services which directly competed with Red Hat's products. I much prefer that trademark licensing for projects intended to have multiple vendor support be administered by a vendor-neutral non-profit who isn't looking to garner competitive advantage in the marketplace by excluding other vendors from being able to use the mark.