I’ve actually heard it seriously proposed (some think tank’s paper on a blueprint for American military power in the 21st century) that it’s the Army that should be disbanded, leaving the Marines behind to fulfill the role of “boots on the ground”.
The argument was basically that the Army is a 20th century organization built to fight nation-level conflicts that are extremely unlikely to occur in the 21st century because nuclear deterrance has replaced “huge army” deterrance. In the 21st century it’s going to be assymetrical warfare requiring more special forces. Keep the Marines to retain a traditional ground combat organization, but move most money into special forces, drones, and intelligence gathering.