Scott's open letter is about Adobe's decision to only allow owners of the most recent versions of Photoshop and Creative Suite to upgrade to the CS6 versions, when they become available. What that means if you didn't upgrade to CS5 or CS5.5, and are still on CS3 or CS4, you'll have to pay full price if you want to upgrade to CS6. This has put the many people into a financial quandry.
The rumblings across the blogosphere following an announcement like this often turn to changing software packages. GIMP always comes into play when people talk about full (and free) alternatives to Photoshop. While I applaud the work people have been putting into GIMP, it's just not an alternative to Photoshop. I have to rely on Photoshop as my main source of income, and since I work on it 9 to 10 hours a day, it's become an extension of my arm. No way could GIMP do half the things I need it to do. The same go for several other PS alternative packages. Some have very nice features, but no one package can replease Photoshop.
I also don't see GIMP ever getting past PS either. It's been around since 1996...that's 15 years now to surpass Photoshop in terms of usability and user base/usage (which is important when working in a workflow environment and exchanging files between clients with different color profiles for instance). It's always "one day this will be great" type of thing. Sorry, some of us have a lot of work to do and can't wait for that day. I do want there to be a viable alternative to PS because I don't like Adobe's practices, but GIMP isn't that alternative. It's been 15 years of "just wait until the next version!".