There are plenty of things that are useful and that have gone away. As long as GenAI stays unprofitable, it has every chance of disappearing if it stays as useless as it is right now.
There's people running stable diffusion locally on their systems for their own amusement. Do you think that will go away?
100% yes, at least down to a rounding error. If people stop pushing billions into training new versions, then the novelty will wear off very quickly. There are still many constraints on what it can do and people will generally lose motivation when they start finding those invisible boundaries on its capabilities. It'll be effectively a dead pursuit.