Nobody is advocating that we build more 4 decade old reactors. On the other hand there are plenty of people suggesting that we not build new reactors. We aren't seeing an attack on old reactor designs, we're seeing an attack on the "other option" you listed.
the real political and economical power is with the current nuclear industry which doesn't have other designs. Any permit to build if given in the next 10 years would result in a new old nuclear plant. Like any powerful established industry they protect their position with heavy regulations and wouldn't let any innovative outsiders in.
The reactor designs are newer, but we also need newer designs for management and disaster prevention/response. Even with the crappy obsolete Fukishima reactors, we would have come through this event fine had there been a (much) bigger investment in those non-technological areas when the plant was built and over the decades since then.