60s space tech also hit a lot of limitations of computers of the time. SpaceX's Super Heavy is in some ways a reimagining of N1's first stage, but with control software that makes it viable to deal with engine failures in flight.

But a big problem is also that the progress in space tech wasn't organic. There was no economic incentive, it was driven purely by propaganda, national pride and political goals. Once that fell away it took half a century for economic usecases catch up to a point where private investment was viable.