I like the idea of the passively-safe, waste-reducing LFTR but it's still a materials science issue at this point, and there's no real solution in sight.

Fission still has this huge stigma about "nuclear=dangerous and bad" which clearly isn't true with the growing number of passively-safe designs... but nobody wants to fund development of those into proper commercial reactors.

Meanwhile, fusion is still different and futuristic enough to have support from governments and the general public.