I used to design fire engines. I learned a lot of really good lessons about designs and specifications. You have to define the roles for your machine. If it is going to do more than one task, which task is more important? We had a lot of customers that were combining two old trucks into one new one. That was fine as long as they understood that it wouldn't do either job as well as a truck that was specifically built for one task. We usually saw this with small towns who couldn't afford to keep running two trucks because of a limited budget. The US Govt, is not a small town. They definitely had enough money to keep their fighters, ground attack and other warplanes as different models, especially since there wasn't a whole lot wrong with them.
Flawed concept aside, this program has been horribly managed, that's where the real problems come in. Lockheed didn't even finish designing and testing the planes before they started production. Then they start jacking the price up and soon we come to our current situation.
Now I work for a place that actually makes parts for the F-35. As far as the "save all the jobs" part of Lockheed's argument, we'd be just fine without it. In fact, most of the surrounding community doesn't even know what we make or care how much we get paid for it.