There's a lot of myths to unpack there. First, the USA is completing 2 new reactors in Georgia. As for accidents, the current fleet is run very well, and newer designs like the AP1000 design in Georgia are dramatically safer.

As for fusion being "the holy grail" not so much really for a few reasons: 1. Fission is so much easier to accomplish with the benefits of a clean waste stream, 2. As for efficiency, it depends on what aspect. For net energy return on energy investment, we shall see when the ITER project is completed in France, and conversion that depends on how much of that heat can be converted to electric energy. 3. The waste stream of fission is an easy to manage problem, especially relative to fossil fuels (zero management). 4. Gen 3 and 4 reactors take on the emergency cooling issues very well, and especially the scaling factor of the new reactors from Nuscale offer a repeatability to make a faster mass scale deployment.

So fission may not be perfect but fuels with far less energy density have made energy revolutions before (coal). Fusion just may end up needing a support network of fission reactors in order to make it cleaner from end to end, and if you're at that point then why add the extra layer of complexity with fusion? To me, fusion is a distraction from an already vastly superior fission reactors we can build now.