There are multiple shipping corridors through areas with less than stable/friendly governments. Sure, there are the pirates off of Somalia, but there's also governments that could threaten blockades or charge steep fares to pass by. Check out this map and consider how many ships are passing by China, the Middle East, and Africa.
"there's also governments that could threaten blockades or charge steep fares to pass by. Check out this map and consider how many ships are passing by China, the Middle East, and Africa"
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.
Consider the annexation of Crimea. That's what happens in a power vacuum or a reduction in the belief that the US and the global community will retaliate against land grabs.
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.
"Consider the annexation of Crimea. That's what happens in a power vacuum"
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].
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...