We don't know how much warning Apple gave them. To be fair, two months to update such beastly products is really nothing, especially when you have to change core functionality (like on-screen rendering in an image-creation tool...). I'd say 4 to 6 months would be an acceptable turnaround time for the most important products.
Compare with Microsoft, which simply won't support retina "for the time being"...
It's frustrating how long it is taken Adobe to update their software for Hi-DPI.