But nuclear power has never been the ultra cheap clean power slam dunk you're portraying. I've been hopeful someone will come up with a clever innovation that changes the cost numbers, but so far every attempt has tanked.
With hydroelectric dams, there is an urgent motivation to bring many of them down: ecosystem collapse. It hurts to lose the storage capacity, but there's a growing awareness of just how severe the damage has been. I don't expect Grand Coulee to come down any time soon but talking with someone who does modeling related to this for NOAA made clear a lot of them are going away.