Not true. Technology is making breakthroughs because that is what technology does. Solar and wind may not have moved along quite as fast but they would have moved along. We need nuclear for stability (as we don't have energy storage facilities that can handle extreme weather events for days or weeks) and we need solar and wind because who can afford to give up "free" energy that is there for the taking. Solar is the end goal (or fusion) of course but energy storage density at grid scale is decades off. There are several viable nuclear designs available now that can't go critical and are practical with just a little more work and government support.