hval
US Army had troop and cargo ships (1,500), landing craft, hospital ships, cable ships, port repair ships, aircraft repair ships and many others.
But nothing like Destroyers, Cruisers, Frigates and so forth?
Indeed why didn't the USAF take over the USN?
Good question, though this is possibly a good thing they didn't.
Did Admiral Rickovers role with nuclear submarines play a small part?
His work on nuclear power for submarines started in 1949 so I don't know.