What does a huge socialist country like America need with a navy?
The answer to both questions is: you really find out why you need a navy when you don’t have one.
Having a powerful navy prevents a lot of threats: these are threats that never come to pass because would-be enemies know that certain forms of global competition are simply a waste of time.
For instance: if there was no US Navy and no Indian Navy, there would be an adequate Chinese Navy - and no independent Taiwan.
The answer is really simple: America has not fought a genuine naval battle since 1944 because we clearly have the greatest navy the world has ever seen, and everyone knows it.
That little factoid has saved us phenomenal amounts of blood and treasure.