This is spot on. The economics is what really kills nuclear. The cost to build and operate a plant vs the revenue you get out of it won't break even until 25/30 years. Compare that to a natural gas plant that'll be profitable in ~5 years.
You'd think this is the kind of thing where governments would step in with subsidies, but that gets halted due to oil and gas lobbyists.
I work in Energy storage. Pretty much all new plants are outdoor in shipping containers, placed far enough apart with venting and deflagration panels to limit any particular thermal runaway from affecting the whole plant.
There are definitely other concerns, but fires aren't.