To my point (and I guess the point of the DRM issue), that would depend on if you could actually get a copy of Photoshop working. Would Adobe still be running their activation servers? Would any of the cracks still be around? I'm willing to admit I don't know if there are FOSS (or equivalent) .psd software. Maybe GIMP will still be around, if it can open .psd?

Sure, it's an issue. PSD isn't actually all that opaque though (Adobe has published some specifications for it).

I guess most consumer formats are pretty broadly supported by open software, most of the hard to access stuff will be pretty specialized.

People have learnt from the UK "Doomsday Book" laser disc problem.

(http://en.wikipedia.org/wiki/BBC_Domesday_Project)

I see little evidence people have learned from it. (And the main lesson seems to be: if you give the national archive office a disc, they will lose it. If you painstakingly reconstruct the disc and give them a fresh copy, they will lose that too)