I totally understand where you're coming from, typically with software projects canceling the whole thing is not the answer. However, military aircraft are a fundamentally different proposition.
If the military goes forward with the JSF, they are going to be stuck with a fundamentally poor platform for at least 20 to 30 years. This thing is wildly over budget, and will be wildy more expensive to operate than projected. This plane is supposed to be the backbone of US air power for decades.
If you scrap this program and start over, maybe it'll take 7-10 years to come up with 3 new aircraft for the 3 different roles. You sacrifice a decade to get something that will be far better for decades.
The military basically did exactly that when the F-111 program got off the rails in basically the same manner. It was supposed to be a fighter bomber for the Air Force and fleet air defense aircraft for the Navy but the Navy version ended up being too heavy and poor performing so they scrapped it, and ended up developing the F-14.
Honestly I would scrap the Marine Corps variant altogether. The USMC never goes where the Navy is not going to be so they could rely on close air support from the Naval variant. Sure a VSTOL aircraft could take off from a field somewhere but that capability simply doesn't provide enough benefit to offset the cost.