When someone says I have a product, device, or machine that can do everything in a given specialty, that is a MAJOR RED FLAG. There has never been such a thing, and never will be.
It was funded as political payback and/or cronyism. Gov’t at its finest.
The problem with almost every military project I’ve had experience with is that the military wants it to do everything. Take the Future Combat Systems family of vehicles. It was one of the most expensive disasters in our history. The military could not make a single decision because any decision automatically ruled out alternative options. Put the engine in the front and you limit some capabilities or make them more expensive. Put it in the rear of middle, the same thing happens. That’s just one of the technical details. There were dozens more, each of which would have limited what the vehicle could do. Shall it have treads or wheels? Should it have slab sides or sloped armor? And, then there was the idea that one vehicle base could be a main battle tank, a hospital vehicle and a command vehicle. Each of those is really a separate design.
I suspect the F-35 is the same disaster. Will it be a fighter or a bomber? Will it fly high and fast or low and slow? Make any of those decisions and you embark on a path that limits what it can do on other missions. Apparently no limitations are possible, so it gets very expensive.