I sometimes wonder if in the near future we'd have programming historians to dig up old brilliant but forgotten ideas, which were not feasible back then, but might add value now with our new computing capabilities.
Artificial neural networks, which underlie most of deep learning, is an example of that. Maybe not totally forgotten, but set aside multiple times in history due to issues around practicality. There are probably a few more of these out there, but it's one of the best known ones.