Th-232 takes ~12x longer to beta decay into a fissile nuclide after absorbing a neutron, compared to U-238. This greatly increases the odds of absorbing a second neutron prematurely and becoming a useless isotope. Moreover Pu-239 releases 2.9 neutrons per fission vs 2.5 from U-233, and the U-238 naturally comes with a significant percentage of fissile U-235. There isn't any significant price difference between uranium and thorium to justify the additional difficulty of using thorium.

I'm guessing people are Never because nuclear isn't going to be widespread in the future, right? Because geothermal/solar/storage is getting too good? And because old nuclear plants will still be around?

@makoyass see here for the prediction market about which sources of energy will be used: https://manifold.markets/JonathanRay/what-percentage-of-us-energy-will-b

What percentage of US energy will be produced by each source in 2050?

Data will come from an official source like https://www.eia.gov/energyexplained/us-energy-facts/