Using dollar figures to judge military strength is questionable at best. A dollar spent in China goes further than the same dollar spent in America (WRT defense)... this also means that % GDP is not that useful either, other than assessing the defense burden on the overall economy for a particular country.

The US seems to routinely make bad investments in defense and seems to waste a lot of money in efforts that have little or no payoff. A lot of this money goes into deep R&D that has no payoff until a generation or two later in the weapon design/development cycle.

This is the danger of being at the bleeding edge of military technology development. The US had workable stealth back in the late 80s. Our current stealth technology is probably markedly superior that anyone else's--but the payoff for that difference is less than it used to be because of counter measures development and the fact that others also have SOME capability.

An analogy (maybe not a good one but I think it is illustrative): Nuclear weapons were VERY useful when we were the only ones that had them. Once someone else had them, their utility approached zero--at least in actually using them.

The utility of stealth has not degraded so much because the power/use dynamics are not quite the same.

As I see it we have some major problems WRT defense spending/development:

1) We spend a lot (I mean a LOT) of money trying to do things that are at the very edge of possibility given current knowledge/technology.

2) we spend a lot of money trying to make things do 6 things instead of 1 or 2 things.. or to be used by services with very different requirements (like the F-35) in the name of "economy" or interoperability. This usually does not actually pay off as you end up with less capable, more expensive systems with LONG development cycles and huge up front costs... and instead of buying 3,000 of them that we actually need, we buy 200 and move to the next generation (while letting actual operational requirements go hang).

We seemingly spend a lot of money and effort just keeping defense contractors busy/in business. I do not want to venture how many development cycles and trials we have done over the last two decades attempting to develop things like new rifles and gear for infantry (that never went anywhere).

3) We are HEAVILY invested in legacy systems that may or may not be useful in an actual war against a par or near par military. My primary example here is aircraft carriers.

A CVN is a HUGE investment in time and money. Gob-smackingly huge. That is why the US is the ONLY country that has any REAL aircraft carriers (we can pretend that these Chinese, Russian, and British ships are aircraft carriers, but in the end we are pretending they are).. No one else can afford it, nor do they have the expertise to operate them effectively... and they do not actually NEED them.

A CVBG is an awesome power projection tool to be used against non-par militaries in locations all over the globe. The air wing of a CVBG is more powerful than most countries entire air forces.

I am not convinced they would be useful against the PRC or against the Russians (the Russians mostly because of geography, the PRC because of countermeasures they have developed).

This investment in legacy systems is not merely an investment of money or time--it is also an investment in doctrine and leads to not pursuing other approaches/technologies. An example here is the continued emphasis placed upon battleships in the interwar period and early parts of WW2--particularly once the efficacy of carrier-based airpower had been conclusively demonstrated. The Japanese were particularly bad in this respect... and this was driven by institutional and doctrinal pressures rather than military effectiveness.

We also probably have the most risk-adverse and casualty sensitive military and society among the major powers... and we have issues with maintaining civil determination in conducting wars and military operations.