If that's what he said, he has a grossly oversimplified view of the difficulties of space travel. It's not that we lost interest it's that orbital velocity is incredibly hard and escape velocity is even harder. Until a breakthrough in propulsion or materials comes along we're going to be stuck on one planet.
I've been thinking about this since you posted it, and I'm not sure that I buy it. I know that climbing out of the gravity well is very difficult, but it hasn't become any more so since Apollo 17 brought crewed spaceflight beyond Earth's orbit to an end. In 1972. Nearly 40 years ago. Using technology developed back in the 1960's. I was thinking about this when the final Space Shuttle mission ended. The Space Shuttle first made an orbital flight more than thirty years ago. The Russian Proton rocket first flew in 1965. I don't doubt that Proton, like the Shuttle, has undergone development since its first flight (the latest model first flew a decade ago), but could we not do better today if we only wanted to? Compare the pace of progress in space-launch technology with that in areas we really do care about, like mobile phones and killing people.
I think there is something in Jeph's idea that we, or at least our rulers, just lost interest. The technical hurdle has not grown any higher, but we're achieving less in leaping it than we did in 1968. The political motivation for Apollo was primarily international dick-waving, and using space-flight for that just went out of fashion, until arguably my homeland started treading the same path.
I dont really get your posting.
Yes the technology to reach the moon is known now. Its chemistry. All our rockets use chemistry.
Chemistry has a simple property: the most powerful reaction of all chemistry is the one of hydrogen and oxygen.
So yes, our most efficient rocket designs use exactly that, hydrogen and oxygen.
So yes, there is no way to store more energy into a rocket. The Saturn V used it. The Space Shuttle used it. Neither are pure hydrogen / oxygen concepts, but the overall performance is close to maximal to what we could possibly do.
We cant go further than that because there is simply no technological way known to us, not even at the far horizont, that would allow us to pack more energy into a certain weight. Nuclear reactors are crazy complicated and super heavy machines. Solar energy is much too little at a time that you could get something into orbit with it. The space elevator is a nice idea but I doubt that it will ever work even if we find a material that could theoretically do it. Just realize this material will be bombarded with our own garbage in orbit.
So there has been no huge progress in this area simply because we have no real option there.
Once someone finds a way to create the "impulse drive" described in Star Trek, i.e. a drive that accellerates small amounts of matter to extreme speeds compareable to those in the large hadron collider, and another technology that is as efficient as nuclear power, but with much less radiation issues and thus can be created very lightweight, we can have something like a star trek shuttle and fly into orbit and beyond easily.
But there is no such option available to us right now.