I'm as opposed to wasteful spending as anyone–and I think that we have plenty of it–but this idea that the US military budget is strictly and solely about shooting wars completely misses the point. It has held together the world's first peaceful, global free trade in exchange for cooperation in security policy since 1946. That isn't cheap.
Nor is it easy or even viable for anyone else. It's not that anyone else could do it if only they had the budget, there just isn't another piece of land on the planet that could do it, short of assuming some impossible alliances.
When comparing military budgets you need to compare what it is they're buying: no other country is providing global free trade with their budgets, so of course they're comparatively small. And of course running an insurgency against occupying forces is relatively inexpensive. Of course regional security is less expensive than global security. This isn't comparing player stats on Street Fighter to see how they'd match up in some kind of March Madness bracket.
Like it or not, most modern wars (at least the non-pointless ones that aren't mostly about pork and politics) aren't about winning or losing in classical terms, but about how they fit into the broader security and trade context.
Who is threatening global free trade? Pirates? Are they why the US needs eleven supercarriers?
https://www.wired.com/2010/01/global-shipping-map/
The carrier fleet is more about maintaining the two-front fight capability. It sounds like the military is shifting away from that strategy however:
https://www.bloomberg.com/opinion/articles/2019-06-11/two-wa...
That's ironic considering that it's the US who has been harassing Chinese and Iranian ships [0], [1]. In fact, the US Navy is a major threat to China that heavily relies on the sea routes for its import and export.
"threaten blockades"
If you meant Iran threatening retaliation with blockade of Saudi's oil shipments, the US is the part of problem, not of the solution. Any other cases?
"or charge steep fares to pass by"
Any precedents? Especially considering that almost the whole world has ratified the United Nations Convention on the Law of the Sea[2]. The whole world except the US, I mean[3].
Think of it, the whole world lives by the law, which the US refuses to be a subject to, and you are talking with a straight face about the US deterring other countries from breaking it. The world is doing fine without American policing.
"The carrier fleet is more about"
And the carrier groups are responsible for the bulk of the US naval military expenditures.
[0] https://en.wikipedia.org/wiki/Yinhe_incident
[1] https://www.bbc.com/news/world-middle-east-49589075
[2] https://en.wikipedia.org/wiki/United_Nations_Convention_on_t...
[3] https://en.wikipedia.org/wiki/United_States_and_the_United_N...
What happens when the US's eleven supercarriers are not in the Strait of Hormuz or floating around the Pacific. The threat is enough to guarantee countries think twice about annexing their neighbors provinces.
Yeah, let's consider it. It's a direct response to the US-sponsored coup in the Ukraine and the threat of NATO expansion into Ukraine.
The Crimea was (arguably) illegally taken from Russia and assigned to the Ukrainian Soviet Republic in 1954 when they both were a part of the USSR, the Ukraine refused to give it back when it declared its independence and yet Russia did nothing about it for a quarter of century and paid huge rent for Russian naval base located in Crimea.
The prospect of American military bases appearing in the Ukraine was unacceptable for Russia and what happened next you've read in the news.
That's what happens when the US meddles around the world.
"The threat is enough to guarantee countries think twice about annexing their neighbors provinces"
But who would protect countries from the American threat?
The US with the support of its navy invaded Iraq in 2003, bombed Libya, protects its allies (Turkey, Saudi Arabia) when they sponsor terrorists in Syria. The Turkey has de-facto annexed part of Syria, the US are controlling oil fields in another part of Syria, over a million are dead in Iraq, Libya is in a state of civil war ever since American bombing.
Well, yeah. There's a good reason why those became uncommon. But it's hard to tell how each state actor would behave if they treated their nearby international waters as their own.
Oh, right, now I know the purpose of 11 supercarrier groups. Pirates.
"But it's hard to tell how each state actor would behave if they treated their nearby international waters as their own."
Why would they do that? They all voluntarily have got bound by The United Nations Convention on the Law of the Sea [0], the US being one of the few countries that refuses to ratify it [1].
[0] https://en.wikipedia.org/wiki/United_Nations_Convention_on_t...
[1] https://en.wikipedia.org/wiki/United_States_and_the_United_N...
Russia gets to operate on the cheap since they have a much simpler and tractable goal - they don't need to be a global hyperpower, they just need regional dominance. They don't need to sustainable project conventional power to the other side of the globe - they only need to project power in their region, while having sufficient unconventional power projection (read nukes).
Russia also gets to operate on the cheap since they have just less commitments.
Finally, Russia also gets much looser constraints to operate in. Consider one of the more "realistic" fantasy war scenarios - Russia moves on the Baltic States. Russia is more likely to be able to absorb causalities politically than American forces. This plays into American force and war planning. There is an understanding that American forces require significant overmatch to create conditions where the current American way of war can be sustained long enough to achieve American goals without too much political/public backlash.
Relevant reference: War is a Racket by Smedley Buttler - https://en.m.wikipedia.org/wiki/War_Is_a_Racket
The explanation offered to the world by the superpower was: Everyone failed. Yet, no one of those in high positions in the security aparatus of the superpower who has failed at doing his highly responsible job has resigned and no one was prosecuted.
What sounds like a (bad) fairytale really happened. Over 3.000 people died that day and many more thousands have died and are still dying as a consequence of what happened that day.
Attackers budget was probably 0.00...1% of the budget of the superpower.
It goes without saying (as it has been said 1000 times over) that the Taliban was able to befuddle the largest and most technologically advanced military in history for 20 years. Tech and the MIC isn't the problem.
Like many other things, there's probably a power law distribution in terms of the cost of reaching certain levels of military capability.
It might cost 10% as much as our budget to get to 75% of the capability, and 80% of our budget to get to 90% of the capability.
The military question is: is that high-end stuff war decisive or not? Or can you win a war with a better strategy or just more of the cheap stuff?
Bringing up terrorism is a red herring. Terrorism gets lots of attention but it doesn't win true wars. You'd need hundreds of 9/11 events to even dent the US's war capability. A war with a nation state is very different from "asymmetric warfare" against a diffuse enemy motivated by an ideology or a set of resentments rather than a true chain of command.
The obvious counter of getting stuck in Iraq or Afghanistan, there the problem is a political, not a military one. The US forces were easily able to archive military targets, the problem is that nobody bothered to formulate clear political goals that could be archived, and consequently the western forces are stuck in limbo.
To say that military Y has a mere x% of our budget and therefore we should win is a gross oversimplification of the complexity.