Possibly the reason it hasn't happened yet is the inaccessibility of robot hardware; nobody else can try different approaches to compete because nobody else has anything like Atlas. Maybe that moat can keep them ahead for a long time, but if the hardware ever becomes cheap enough for real applications, it will be cheap enough for plenty of competition. They will have to adopt more ML methods or be disrupted. Of course maybe they already are, it's not like I actually know how their stuff works in detail, but consensus seems to be that it's still mostly control theory in there.