Wouldn’t it be an obvious part of the price they will pay for the electricity? The electricity producer or whatever intermediate in charge of the waste, will bill its work for waste storage, and it will end up on the bill of the energy consumer. What am I missing?
Long term storage is not supposed to require maintenance over that time, the worry is rather preventing people to dig them up unknowingly in the future. Actually dangerous wastes have way smaller half lives that that.