For the first few decades after WWII, the rocket and space industry was run by brilliant engineers. After Apollo it got taken over by mba's and political types, and basically stagnated. That is why you have SLS which is actually inferior to Saturn V.

But then Musk took over and once again a brilliant, innovative engineer was in charge, and so we are back to making real progress in space travel.

By the way, I am not talking about the space probe designers. They have been brilliant, and have produce an astounding series of scientific advances. But the rocket industry has stagnated.