Regulation is the scapegoat for nuclear's failure, but it's equally the case that regulation is vital to nuclear (and to nuclear getting liability caps.) If the risk of nuclear were not socialized no one would build it (or insure it).
What has also prevented changes from happening is that nuclear scales down poorly, so the cost of iterating designs is so large. Making a new kind of PV cell or module, or wind turbine, is comparatively much cheaper, because these are individually much smaller and cheaper. The replicated nature of these sources is an advantage in so many ways.