[pfdietz]

Why should fusion be radically cheaper? It's very complex, has much lower power density than fission, and pushes materials and systems more strongly (power/area through surfaces, for example; neutron flux as well) than fission.

If you claim either fuel cost or waste handling cost, neither of those is a major part of the cost of fission power. Capital cost is, and fusion moves that in the wrong direction.

[pas]

Fusion is "cheap" if the externalities are priced in. (Of course that's currently a very big if.)

But even then, assuming a version of "fusion tech currently in R&D" realized today, we can probably build a lot of windmills and battery parks for the price of one fusion power plant.

Again, on the long term it seems ideal. (It can be made portable, abundant fuel in the universe, safer than fission, etc.)