No. Like Nvidia, ATI only really cares about people on Linux that provide the most profits... which is to say professional workstation types using Linux for scientific visualization, 3D movie editing, blah blah blah. Those people use Redhat. For most of them they require support contracts and hardware support and if you want that then your going to be using Redhat as Redhat has the industry support channels and partnerships established with a lot of hardware/software vendors. This is why Redhat continues to make money.
That is also the only reason you have proprietary drivers in the first place. If it was not for those markets preferring Linux over Windows then you would get nothing. They'll continue to support consumer hardware because that gives them a useful debugging tool. They can't expect just to target Redhat and get a reliable product. Fedora and Ubuntu represent essentially development versions of Redhat.
To put it another way... they'll get around making it work for you in Ubuntu, but only until after they get more important things done. Everybody works for a living, everybody has to eat and most have families to take care off... etc etc etc. Be happy that Linux is profitable for them to provide some support.
Also this is why OSS drivers are important. They simply enable people to get hardware to work/work better even when there is no significant/direct financial benefit for ATI. It helps break some of the dependency on AMD itself, which is a good thing for everybody involved.