The Marines did an absolute ton of amphibious work in the Pacific. All the island hopping in the Pacific had Marine elements, particularly Iwo Jima. WWII was just so big that we needed the Army to do both Army and Marine jobs in Europe, and they were needed to assist in the Pacific as well because we are easily the largest of the services. Marines have always been small, and they just weren't big enough to do all the Marine missions themselves. We actually still have this problem today, manifest in other ways. We have lots of jobs that should be done by Green Berets, such as the training of the Afghan Army and other forces around the world. We end up using Marines Special Ops and Navy SEALs to help out with these missions, even though that's not what they do because we simply don't have enough Green Berets for all the work that needs to be done. Everyone likes to poke at the bloated defense budget, but we still don't have enough people to do all the stuff that's asked of us. Look beyond the really big number, and you'll see how thin it all gets spread.
