My guess (as an engineer but not in that field) is that some sort of breakthrough is needed or it will be a long slog. The general problem of robots navigating

My guess (as an engineer but not in that field) is that some sort of breakthrough is needed or it will be a long slog. The general problem of robots navigating arbitrary spaces will probably be solved by wider advances in machine learning. Because a robot mapping its environment, planning its motion, and carrying out that motion while adapting to the dynamic environment, isn't being treated as a classic control systems problem any more, but fed into trained nets. It's too broad a problem for even sophisticated control systems, in the general case. Even once robots can do amazing things, there needs to be an economic use case that's compatible with what they can do, how they're powered, and how long they can work for. Similar to quadcopters in a way - they have changed the world in some limited ways, but so far they haven't scaled up to carry people or out to deliver parcels, so they remain niche. If someone figures out one day that robots can deliver burritos/assassinate dissidents/stack shelves efficiently, it could be a quick takeoff.