I think this is an interesting discussion to have for the simple reason that it presents a perspective more than an argument. If by "Age of Space" (capitalization included) we're talking about the Cold War grandstanding that masked a staggering amount of militarization in the name of ideology and profiteering, then yes, that age is largely over. If we're talking about the "space age" then I'm a little less maudlin.

The perspective presented in this essay is largely naive and wholly American. I mean,

The first, simply put, is that the United States has lost the space race. Now of course it was less a single race than a whole track and field competition, with the first event, the satellite shot-put contest (winner: Russia, with Sputnik I), followed by the single-orbit dash (winner: Russia, with Vostok I) and a variety of longer sprints (winner: much more often than not, Russia). The run to the Moon was the first real US gold medal—we did half a dozen victory laps back out there just to celebrate—and we also scored big in the planetary probe toss competition, with a series of successful Mariner and Voyager missions that mostly showed us just how stunningly inhospitable the rest of the solar system was. The race that ultimately counted, though, was the marathon, and Russia’s won that one hands down; they’re still in space, and we aren’t.

Context matters here - when Sputnik went up, we were overflying the Soviet Union with U2s. Contrary to popular myth the Soviets not only knew it, they'd registered protests in the UN and routinely fired 10-20 SAMs at each flight. It was an untenable situation. Fortunately the USSR obliged Eisenhower by launching Sputnik, thereby providing justification for constant overflight by satellite and allowing Ike to shift surveillance power away from the USAF.

Also worth noting: the USSR regarded the space race as submariner duty. It was dangerous and people died all the time. for the United States, on the other hand, death of our national heroes was absolutely not an option. Part of the reason was that Soviet automation and computerization was decades behind the United States; we could automate a lot of shit while the Soviets had to put people up there. We had one manned spy satellite on the docket. It died in committee. The Soviets, on the other hand, lofted three. And while we gave up on our "throw up a bird" approach to satellite surveillance in the '70s, Russia shows no signs of letting up.

The US puts less hardware into space these days because the US needs less hardware in space these days. What we're seeing is the function stripped of the bravado and flag-waving. The Mars Opportunity Rover has been doing science for ten.fucking.years without a break - Apollo 17 spent three whole days on the moon. And yeah - there's less bravado for a robot than there is for three dudes but 3.2 million people watched Curiosity touch down on the web alone.

Right now, we're experiencing a lack of organic need for space. I'm not sure we'll ever achieve the pressing drive we had when our true purpose was ideological in nature, but I am sure that whatever happens next will come from a healthier place.

You climb the mountain because it's there, true. But as Al Gore pointed out, if you could somehow fill the Orbiter's payload bay with feathers and magically turn them into gold in space, you would land having lost only a half million dollars in the process. There's mountains and then there's monumental cost overruns. Enough delta-V to cross the Karman Line will never come cheap... but the arc of history is long and it bends towards MC^2.