[pixl97]

So most the specialist problems we've had that were not 'generalist hard' we've already mostly solved with machines that we don't consider complex robots.

It shape of the robot isn't the issue, the problem space of reality is. A roomba can suck stuff off a floor, it has a much harder time dealing with (or even identifying) a sock that needs moved out of the way first. To do that for all the different objects that could show up in front of you, you need a general purpose AI.