It was a pissing contest between the superpowers.
That doesn't mean there's less merit in that. In fact, what they did in the '60s was a heck of a lot harder, achieving so much with less tech, and hewing a new path through a virgin jungle.
It simply means - and explains why - those achievements didn't last. We put in a humongous effort to reach so far, but once the initial impetus died out, we had to scale it down.
Well, now we're back.