Ex did bring up a good point, which I'd like to bring up again.
Why spend so much on a piloted aircraft, when UAVs (drones, missiles, etc.) are capable of doing everything and more (or soon will be).
True fact - just read in my Air and Space magazine that the US is training more drone pilots than aircraft pilots now. Kinda shows you which way the wind is blowing.
Also, I'm not saying that UAVs will be any more or less expensive than an F-35. I don't know that.