Would having an full-feature open source driver actually hurt or improve business?
In the high-end consumer market who cares about the open source driver other than the open source purist?
Hmm, "who cares about the high end consumer market"? What about the high end professional market? I have worked in several engineering departments where ALL development is done on Linux/Unix boxes and high end graphics are a must (EDA IC design tools for instance). I'm sure there are many more (closed source) applications that run on open source systems that need high end graphics performance and the engineers demanded the performance/features needed.
Every time I have tried to use the Nouveau drivers, it breaks my windowing system in some way I must tweak just to get working again (Ubuntu 12.04, CentOS, and a few others that I run).
I must be one of the rare instances where AMD drivers/cards just worked well for me.