Chess engines have been defeating humans for 20+ years (and are overwhelmingly stronger for a long time), but that hasn't diminished the interest in competitive chess, because the human element of competition and struggle and deep fundamental appreciation for the game is what makes it worthwhile pursuing.
AlphaGo can play go but it cannot appreciate the beauty of the game (at least as of yet, and I don't think it would make the game worse if it could), and so I don't think there's a meaningful conflict between humans and machines.
If someone invented some sort of superhuman math proving engine tomorrow it would not diminish the beauty of maths and I don't think anyone would quit the field. Just like in chess it ought to motivate people to understand their field better.