2) Read the article that you are referencing please. What you are implying is not the thesis of that article nor is it what Geoffrey Hinton is saying.
What Hinton is saying is, we should throw out deep learning. What he is saying is that the current approaches to AI are fundamentally broken and aren't going to result in artificial general intelligence.
Backpropagation is not just used in supervised learning, it is also used in unsupervised learning. I happen to agree with Hinton, in that there is too much hype around the current state and successes of AI, which has mainly been in "narrow AI".
AI is a term that gets thrown around a lot these days. But there is a big difference between technology that automates the tedious tasks of daily life, and artificial general intelligence.
In the world of deep learning, data is king.