Its not impossible, but it needs someone to figure out how to monetize desktop linux so they can then put the marketing effort in and pay a few companies to port big name apps such as photoshop that would give it some momentum and mindshare. A single profitable desktop would then give other companies a good target to port their own desktop software too, which would encourage more users and get to a virtuous circle.

But without that (and no one has figured out how to do it so far) I agree, I cant see it happening.