Which is more outdated? Army Airborne or Marine Amphibious Assaults?

"Amphibious Assaults" is sort of a misnomer in the modern world.

It's a capability, but it's not exactly the same thing most people envision. we're not talking about the WWII style "Assault" of yesteryear.

Heck, the Marine Corps doesn't "naturally" even function at a level were that can occur. Our largest normal sized standing MAGTF is a MEU with a BLT (Battalion Landing Team), so we're talking a Boat Company, and a couple of LCAC.

That doesn't mean we can't unload a full BLT quickly. We can. But it isn't strictly "Amphibious." We use a combination of Amphib, Air Assault, and follow on operations to make it all happen. The shift from Amphibious to Expeditionary to Littoral operations as warfare has evolved.

So, asking which of the two is more outdated, sort of starts from an odd premise in that we've already evolved past one of them, and the other is used extremely rarely.

The vast network of RallyPoint is predominantly army.

True operational forcible entry at large scale hasn't been necessary due to extensive diplomatic engagements and alliances. The best airdrop or amphibious landing? The one that's unopposed. Carried to operational conclusion this means using an allies airports and lining up on its border to run through (Iraq) is the most efficient method. Our other major war employed a mix, a vertical envelopment ( a heliborne amphibious assault- one of the varitieis) and a (smallish) airdrop in Afghanistan.

In general my arguments about airborne vs heliborne have been made here: https://www.rallypoint.com/answers/is-the-airborne-concept-outdated

So in sum, has either been used the way they were in WWII? Nope. Will they be again? Lets hope not. Should we keep both capabilities around just in case? Probably.

Have you ever kept anything that you haven't used for 70 years just in case? They're neat. They're novel..... but probably a huge waste of money to maintain....