I certainly hate to start an argument here, but I don't agree with you saying that AMD could care less about consumers who use linux. In fact, that is a complete fallacy. They are about to/or just hired a bunch of staff that are required to have linux dev background. They have released their their documentation for the open source world to view and use, plus they also employ a few devs that actually work on the open source version of the Radeon drivers. Admittedly they are a bit slower at implementing some of the newest features and getting the proprietary drivers to work with the newest kernels but they do work on it and also take some consideration into what the linux world is doing.
Nvidia does none of this. All the open source drivers for the Nvidia hardware are build from reverse engineering. Plus Nvidia has said they won't support certain future features of the linux kernel ever. (KMS).
However, with that said, last I checked the proprietary Nvidia drivers are still performing a bit better then AMD proprietary drivers, but I haven't checked it out in about a year and I have heard/read some amazing stuff about the latest AMD drivers.
It isn't just linux that AMD dropped support for the R600 core and older, they did the same on windows. So it's necessary to use older drivers on windows as well. The problem here is that the newer kernels aren't supported by the proprietary drivers for the older R600 cores (and older) so the only way to go with those is the open source drivers. I'm not sure how to do it on Pardus, but you can get some decent performance (even 3D) out of those old AMD cards with the open source RADEON drivers.
Just so everyone knows, I use a Nvidia GTS 250 because I generally use the proprietary drivers, and as I said before they generally perform better. I'm not a fanboy either way.
For loads of info on all this stuff check out
www.phoronix.com. You'll have to do a bit of searching to find all the info cause it's in lots of different articles.
Perhaps someone knows how to use the latest Radeon open source drivers for those R600 cards and older, so that it isn't necessary for the people with problems to upgrade. (depending upon usage of course)
http://www.x.org/wiki/radeonBuildHowTo is a link of a how to.
I can't say for sure, but between the X1000 and the HD2000 cards is when AMD bought out ATI or slightly before. Since that time AMD/ATI has made a huge come back and actually started working with the Linux world (when it was ATI they shunned Linux) so it has all pretty much been rewritten and built up from scratch. I wouldn't be surprised if that is also why support for those cards was dropped.
Nvidia dropped support for old cards as well (stop making new drivers for them) so you have to use old ones that aren't very good like the Nvidia chip on my wifes laptop. (can't remember what it is at the moment. But it is older and the open source drivers is virtually the same but supports more)
Edit: could try adding the testing or dev repos to get the latest, but eventually it should get into the official repos either way.