Self driving cars and intelligent robotics is the real goldmine. But we still don't seem to have the right architecture or methods.
I say that because self driving cars are entirely stagnant despite the boom AI interest and resources.
Personally i think we need a major breakthrough in reinforcement learning, computer vision (which are still mostly stuck at feed forward CNNs) and few shot learning. The tranformer is a major leap, but its not enough on its own.