The costs used for wind/solar energy never included the cost of the required buffer storage, and even the rare few people who include that never factor in frequency stability which to this day is maintained by the giant steam turbines everyone wants to get rid of. It will not be trivial to solve the frequency stability problem; it will likely require massive investment in pumped water storage, flywheel storage, or nuclear energy, and these costs once finally included in the real cost of wind/solar will hurt its value prospect considerably.

As for nuclear waste: the overwhelming majority of nuclear waste generated over the lifetime of a reactor is stored onsite. Only the smallest amount of material is what will actually remain dangerous for a long time, and many countries have already solved this problem. It's a seriously overstated problem repeated by renewable-purists who usually haven't even considered how much frequency stability and grid-level storage have and will add to the cost of renewables, meaning they have not given a full accounting of the situation.