Military procurement bureaucrats listened to generals who wanted too much for too little. They wanted a stealth version of the Osprey that could do the VTOL stuff while flying at Mach+ speeds carrying a huge variety of armaments and payloads.
I think you mean the Harrier (AV8B), not the Osprey (OV-22).
And I for one have long recognized that the first run of just about any military equipment does not perform exactly as advertised. The M-16 was not reliable until the A1, the Arleigh Burke class destroyers were not really world class until the last of the first gens were launched, and the F-18 was originally rejected by the Navy, only being accepted after many years of upgrades and modifications.
And yes, a replacement for the Harrier is badly needed. An upgrade of the Vietnam era Harrier, even the youngest Marine Harrier II is over a decade old, and it is time to start seriously working on their replacement.
And yes, it is still needed. For a Marine Amphibious Force, this is often their only air to air defense when they are separated from a Carrier Battle Group.
I have worked with a great many pieces of equipment in the military over the years, and it had always gone through many modifications, so that it barely resembled the original models. And if somebody has a good eye, they can spot them.
That is a First Generation PATRIOT Missile launcher, a piece of equipment I am very familiar with. That one happens to be a the museum at the White Sands Missile Range (where I have inspected it in detail).
And there is a PAC III 3rd generation launcher. I can spot at least 7 differences in a 1 second glance to tell one from the other. Could the original shoot down an inbound ballistic missile? No. Could the original be rapidly emplaced with the entire Battery ready to fight in less then an hour? No. Was it able to do it's original job and shoot down enemy aircraft within 2 hours? Yes.
In short, I do not see this as a boondoggle. I simply see it as a program that is badly needed, to replace equipment that is dangerously close to the end of it's lifespan.