It would be an interesting move. I would see one or both of two things happening. First, people would take it and run with it, eventually coming up with a decent piece of software. Second, Apple could do the same. Either way, though, Adobe would lose control for sure.
The big question to me is, why isn't Adobe serious about making this technology better? I mean, if Flash worked superbly well we might be not having this discussion. If they want sole control, then it has to work. If they can't fix it, find someone who can, or release it and let the masses figure it out. I think Jobs is right, they're lazy. They wasted a good position.