Omitting the other members of the LBH conspiracy and Schmidhuber is unfortunate, but I agree with the idea that the number one reason deep learning is working now is scale. Hinton also says it himself, for example (at 5m45 in the video below): "What was wrong in the 80 was that we didn't have enough data and we didn't have enough compute power. [...] Those were the main things that were wrong".

He gives a "brief history of backpropagation" here: https://youtu.be/l2dVjADTEDU?t=4m35s