"Anyone who expects a source of power from the transformation of these atoms is talking moonshine." - Rutherford & "It's like shooting birds in the dark in a country where there are only a few birds," - Albert Einstein - The Pittsburgh Press - Dec 28, 1934 - On the idea that man might some day utilize the atom's energy. Einstein was essentially making the same "parameter space" argument you're making.
There will have to be more true breakthroughs to get to AI, yes; I do agree though that it will take a "long" time, however before this happens.
I agree with the problem being more one of finding the 'right model', as I'd hope that this will reduce the parameter space greatly. That's why I agree with gggp's post that we'd need to know more about human intelligence, thus also human motivation.