The regulatory climate in the US is just not conducive to nuclear innovation. The regulatory cost and delays would be a nightmare for a completely new type of nuclear reactor to be taken any further than conceptual modelling. Like Justin said, who is going to pay for it? What company wants to risk that high a capitol in a market that is so risky?
The molten salt reactor will be built, but it will be built in China. China will take the technology Oak Ridge developed in the 50's/60's, finish it, and then sell it back to us (if the NRC is even able to license something so outside of their comfort zone).