Actually, it's worse in terms of cost. In pre1950s America, we weren't required to police the world or otherwise maintain a global military presence.
I think that's a big part of the complaint here. We really don't need to police the world. It's absurdly expensive. We've done it more and more over the past 50 years, and it's hard to see much of a payoff for doing it lately. Part of the reason we do it is because we can. So we're stuck in a circular game: We "must" police the world because we're the only ones powerful enough to do it. We "must" be powerful, because we have to police the world. Sooner or later, we're going to have to question the underlying assumption.
There are more countries today verging on superpower than back when we only had the russians to worry about. At a minimum, there's Russia -and- China, and China has the leg up in both population and economic growth.
That's a very generous definition of the word "superpower." The USSR was a superpower. Modern Russia spends a fraction of what the USSR spent in real terms, and it doesn't seem to be colonizing the world like the USSR did.
China could be a superpower at some point in the future, but they're still well behind us. They also don't seem to be acquiring territory all over the world like the USSR. In any case, China will eventually be a bigger economy than we are, and we're going to have to come to terms with that. If they want to outspend us on military hardware, they'll eventually be able to. They have 4x our population, so they'll reach GDP parity with us as soon as they're 1/4 as productive as we are. We might as well start planning for it. If our only plan is to keep outspending them 2.75:1, we're screwed.
I'd say that playing nicely with others, having a military strong enough to police our territory and core interests, and sitting on enough nuclear weapons to wipe out any aggressor is probably a better long-term strategy than trying to bury everybody else under the sheer weight of our spending.
Using the historical comparison, we should be spending more (or at least the same) than we were then.
Using the historical comparison by what unit of measure? We spend more than twice what China spends and almost six times what Russia spends. And that doesn't even count the amount of hardware we've already amassed over the years of exceeding their spending. How far ahead of the next biggest enemy do we need to stay? Twice as big? Ten times as big? What scenario are we preparing for, exactly, and what are we trading to prepare for it?