It's not entirely the Marines' fault. If there was enough room in the budget to credibly deliver a next-gen replacement for the F-16 and F/A-18 platforms as well as a separate Harrier replacement, the Marines would take it in a heartbeat. The problem is that the Joint Strike Fighter concept is a bean-counting "let's use one plane to meet everyone's requirements" program.
Several specialized fighters would probably be a lot cheaper, and they'd all be a lot more effective too. It's really the requirement of "it has to do everything and then some" that's crippling the design here.
This is due to hard feelings from when the Navy abandoned the Marines at Guadalcanal. Also tradition and territory is so important in the military. They aren't really capable of making some monumental change like doing away with Marine aviation.
It's not so much that (Marine aviation existed before the U.S. entered World War I) and more to do with the fact that the Navy and Marines have entirely different aviation missions. The Navy specializes in fleet defense, naval warfare, and light bombing while the Marines specialize in close air support. Different mission specializations, unsurprisingly, call for entirely different technical requirements. Even if the Marines didn't have their own aviation, they would still need close air support from the Navy, and the requirement for a STOVL aircraft would still exist.
The Marines specialize in close air support, and for that role STOVL is incredibly useful. It's the only way to effectively deliver close air support with a jet aircraft.
The Harrier is still flying. The F-35B is set to replace them but since that aircraft hasn't been manufactured in large numbers yet, the Harrier remains in front line service and likely will for many years to come.
> The U.S. Marine Corps has extended the retirement date of its AV-8B Harrier IIs in increments until 2030, and most of the fleet will remain active through 2027, according to Boeing, which supports the 1980s-generation strike aircraft. Harriers were originally scheduled for retirement in 2015.
> The Marines specialize in close air support, and for that role STOVL is incredibly useful. It's the only way to effectively deliver close air support with a jet aircraft.
No, STOVL is the only way to deliver CAS from the combination of improvised forward ground bases and small-deck carriers that the Marines want to their air elements to operate from to keep up with the rest of the Marine force.
Fixed wing, non-STOVL jets (like the A-10) are fine for CAS, but require different basing infrastructure that isn't consistent with USMC operating needs, hence the AV-8B and the requirements for the F-35B.
Well, unless you want to replace all of those amphibious carriers...
CAS requires low airspeeds as well, which is a major benefit of STOVL aircraft, which can have arbitrarily low airspeeds on account of their hover capability.
