The Thorium Molten-Salt Reactor: Why Didn't This Happen (and why is now the right time?)

From my understanding it comes down to part politics, part feasibility. When nuclear power first started becoming popular light water reactors were easier to make and their fuel/byproducts aligned with the production of nuclear weapons. As years went on regulation and inertia did a great job of cementing us into our old ways. Today, advances in (material) science have made producing molten salt reactors more feasible. They also seem more attractive now that the public is generally very adverse to nuclear waste and power plant failures. I'm paraphrasing what was explained to me so someone that knows more please chime in. Kirk Sorensen has been a major advocate of molten-salt reactors and gave a great Google tech talk on the subject. [this video]

This discussion always leaves out LFTR [link] [link] Top comment: "Advantages of thorium: Much safer than uranium-no pressure vesel, no fuel rods to melt down Much simpler reactor-Thorium salt liquid is pumped from the reactor tank through a heat exchanger and back into the tank Thorium is much more plentiful than uranium--in fact so plentiful it is considered a waste product from rare earth mining Thorium doesn't need expensive enriching to make it usable Thorium is of little use for weapons If power goes off liquid fuel simply drains into a pit which stops reaction. No fuel rods to cool or melt down if power fails This technology has been around for years. Why was it not developed long ago?" [this video]