As a former Army combat infantry man (164th CAG Can Tho, RVN) I object to any catch all comparison between the Army and Marines. The Marines are elite troops, but they are the Shock Troop element of the Navy. The Army has equally elite Shock Troop elements. Comparing the Marines to the entire Army is a fair as comparing them to the entire Navy.
Well of course. The army has a much longer tail, because the Navy is the tail of the Marines even in many onshore operations. IAC, the combat team down south did as good a job as an Marines could have done.
The main task of the USA is to defeat/invade and occupy enemy nations. Entirely different tasks and both do thier task extremely well.