I'm for guarded optimism here. The reality is that getting regulators to wrap their heads around it is a real cost. The public doesn't trust nuclear and these smaller ones don't produce medical isotopes, so regulators can't even fall back on saying grandma needs it. When the public says "why not solar?" the government should have a good answer. It makes sense in Canada (history of safe nuclear, large population base with knowledge in engineering, etc) but it doesn't make sense in Saudi Arabia short of nuclear arms capability.
Regulation is a serious barrier in the U.S. but Canada is a lot more rational about new technologies.
Simple answer to "why not solar" is that we need power at night, and it's not clear that storage at large scale would be cost-competitive with molten salt reactors. (I think nuclear baseload with solar for extra daytime load makes a lot of sense, though.)
I once described molten salt reactors to a very anti-nuclear activist in the Green Party, and he said "hmm...that actually sounds pretty good."
