So you think the Army is more capable than the Marines???
I don't mind educated you some more Sparky, someone sure needs to. First, you need to look at the actual purposes of both organizations. I know, they "look" alike to you but they're very different in nature and mission.
The Corps mission is to take strategic strong points regardless of expense, a mission that they are tremendously successful at.
On the other hand the Army is intended to find the more long term war, not individual battles, in which force preservation is an critical element and for which the Corps is not as suitable (in training or doctrine).
Both services are very proficient at their jobs, a distinction I didn't expect an "airman" of your nature to comprehend.