Currently in Suse 10.1 there are 2 different update paths. Yast2, and an autoupdate feature new to suse not unlike windows update. This new update feature appears to have its own rights management and security profiles. On initial install of suse 10.1, the new kernel updates as well as some driver related material were no longer displaying on yast. These updates were only viewable thru the new update service. If I had to take a guess at how these new drivers would be distributed, I would say that this new update service would be the delivery agent.
I have seen an increase of vender supplied linux drivers over the past 5 years or so. Just a year ago, the drivers supplied thru ati were a joke, They have improved by leaps and bounds, tho, a little more integration with sax2 and not having to manualy script installation suffixs on the aticonfig would be nice. Nvidia's support has been fairly consistent, as well as support from linksys and a number of other component manufacturers. Even my latest drivers disk that i received from gigabyte for my dual core, nvidia sli mainboard came with linux drivers.
Short of microsoft making directX open source the biggest thing I see helping the linux community Would be added support for the wineX / Cedega developers. I don't know how many people I have talked to that would be using Linux specifically if it weren't for the fact that they can't play most of their games on it. The big one I play right now is everquest 2, due to the fact that it depends heavily on the 9c api's, I don't see it being supported all that well. It IS sort of a vicious circle. Software manufacturers won't really support *nix unless there is a major user base that will use their software, and there won't be a major userbase, unless there is support from the software market.