RAGE was patched for PC shortly after launch, but it wasn't completely fixed. There have still been issues with blurring textures, but a new patch is on the way that will sort everything out.
"We have a bicubic-upsample+detail texture option for the next PC patch that will help alleviate the blurry textures in RAGE,"said id Software's John Carmack on Twitter.
RAGE released on October 5 and got pretty good reviews. The PC version, however, was marred with reports of visual problems and lacking options. Hopefully this last patch brings it up to speed with the console version, not that I feel that really excuses anything.