Elder Scrolls: Skyrim (Apache Edition)

Who is providing the real fixes for this title? Is it AMD or Nvidia driver teams or Bethesda? After the 11.12 AMD catalyst update I am enjoying smooth framerates and no weird crossfire issues like before but I know that Steam like does the ninja thing with updates and just starts patching away while you play (and don't notice the itty-bitty download bar).

Generally, the developer of the game provides the updates for the games themselves. Their fixes will fix problems with video cards, but video card manufacturers will release driver updates to improve or fix gameplay for their video cards and maybe fix some problems.