As
@Roaming East said, the Marines aren't really an "elite" force. They are a light infantry force designed to invade. Their logistical support is designed to last them 3 whole days, meaning that they aren't designed to do long operations on their own. They are primarily an infantry force with a little bit of air support,
and they rely pretty heavily on the Navy for fire support and logistics, which makes sense, given that the Marines doing the invading are going to be coming from boats. If you're interested, you can check out Marine Expeditionary Units.
The Army, on the other hand, is designed for the long haul. Our command structures put all the units that we will need under one organization, meaning that we can generally get what we need when we need it. We also don't rely on other branches to do things for us. Since we don't plan together, we typically can't get those assets unless we schedule them way ahead of time.