Ten years ago we didn't even have AlexNet; I think most people would have thought a paper like that was nuts at the time. The ten years since are what popularized backpropagation as a path to general intelligence. Who ten years ago would have seriously predicted GPT-3? The odd few that did are certainly not the people I would expect to have been dissuaded! And if there's any actual experimental evidence that backpropagation is not enough, I haven't seen it.