To be accurate, what the Marines originally
wanted was a Harrier replacement that could take care of itself against a low-grade air threat, with teen-series-like agility and acceleration and the Mach that fell out of that performance. That was basically the RN requirement as well.
However, the Marines were then
told that they could have all that
and stealth and that it would cost them less, because the same airplane would be adapted as an F-16 replacement for the Air Force, which would pay for the development and provide the bulk of production orders.
Then big Navy was roped in, because funding this project meant that big Navy's own stealth project had to be cancelled.
But it was still going to be cheap because "salagadoola mechika boola bibbedy bobbedy
ing boo", aka "cost as an independent variable".