Part of the idea to me is that, if you want to be a nuclear civilization, you need government scale investment in not just building plants but in improving the designs.

You need to stay in for decades, stay evolving, where-as France simply isn't big enough, doesn't have enough demand to keep at building again and again (to the scale that they would iterate on new significantly improved fuel cycles).

America's efforts like the Integral Fast Reactor, a fast reactor with on site pyro processing, seemed so promising. A safe & proliferation-safe way to not just reprocess but to keep burning tons of the transuranics (something France doesn't really do, afaik). But we gave up. The related PRISM designs have been kicking around for decades now, and I think one might even maybe get built, but generally the atmosphere around nuclear feels like it's building old/boring designs & not trying at all to advance. Then externalizing the massive incredibly long lived waste problems.

I haven't done any research in a bit, but India for a while was talking a big game about building out Thorium reactors, at scale, and I distantly recall that seemed to have some potential to be an improved fuel cycle over the basic designs/fuel-cycles we've had for so long.