Sure. But why? MSRs don't have any real features that are worth spending that much money.
Modern PWRs are just as passively safe, if they lose cooling and melt down, the molten fuel will be safely contained by the core catcher.
Uranium is also not scarce, and if we want to get into breeding reactors, existing fuel reprocessing is an established industry, on which we _already_ have spent several hundred billion dollars.
The thing about R&D spending is that it is speculative. Even if that question does have satisfying answers; it is unreasonable to expect people to prove that R&D will have a commercially successful outcomes with foresight.
Or maybe thorium reactors ON A ZEPPELIN! With microwave power transmission. After all, if the objective to spend money on research, then what can be cooler than a nuclear reactor on a blimp?
If you actually think that is a good idea you can try to give it a go. There are worse things to dedicate a life to and it might have big applications in disaster recovery scenarios or something.
Modern PWRs are just as passively safe, if they lose cooling and melt down, the molten fuel will be safely contained by the core catcher.
Uranium is also not scarce, and if we want to get into breeding reactors, existing fuel reprocessing is an established industry, on which we _already_ have spent several hundred billion dollars.