It's hard not to, if one is to discuss war. I have to use some country's fighters.
-Penguin
It was a reasonable hypothetical example, I think you're fine.
The best argument towards continuing the F-35 project IMO, despite the upward spiraling costs, is that all the nations we're going to sell them to besides ourselves really want some kind of next generation fighter aircraft. Better that it comes from us (the US) than from the Russians, French, or Chinese. Because if the US doesn't supply it, those other countries will, and then they will build their capabilities for creating and maintaining many nation's aircraft while our (the US') capabilities suffer.
According to Wikipedia on the F-35, 3100 are due to be built for nine US allied nations, compared to 2400 being built for the US military itself. So well over half of the production is going elsewhere, and no matter how expensive the aircraft ends up being, that ratio will probably remain constant. If the US scraps the project, that's a lot of money being funneled to other nation's military aircraft industries, to the benefit of their economy and not ours.
The question is really whether the aircraft is going to end up like the V-22 and eventually be something that can be built and depended upon, or should it be considered a sunk cost and scrapped. Before you say sunk cost, you have to consider all the economic elements, including the costs of putting all the people working on the project into the unemployment line, and essentially outsourcing those jobs to the countries I named in the previous paragraph.