But when people say we're close, I think they mean 1 accidental breakthrough away.
Like the "just add more layers" meme, the solution to the own-dataset creation problem could be stupidly simple, just waiting for some bored student with access to a decent machine to accidentally find it. For example, maybe just giving the AI the right novelty seeking behaviors (like children have) will be enough to get the process kicked off.
My objection to the singulatarian concept of a self improving AI is simply that I haven't really heard a reason to think that there exist intelligence algorithms that are dramatically superior to ours. It is entirely possible that our thinking algorithms are optimal-enough that rapid self improvement leads straight to something not much different from human intelligence, just faster, and in silicon.