Why do programs cost so much? Because they take so long. F35 started 15 years ago. We have built a couple of dozen of 'em. It's been flying for a couple of years. But. All the missiles and stuff are software controlled. And the software to run them isn't ready. They think the software will be ready in another year.
First mistake. All the missiles and smart weapons should not require software support from the F35. There is plenty of room to pack a million lines of code into each missile or smart bomb. The missiles and smart bombs ought to be able to get a hit with no assistance from the launching airplane. Benefit: the missile or smart bomb will work on another aircraft, without requiring a five year software writing fandango.
The old F105 could fly into North Viet Nam, suppress the SAM's, jam enemy radar, dog fight with MIGs, and bomb every target in Route Pak 6. And there was not a lick of software anywhere in that plane. And, the old Thud went from paper spec to flying combat missions in less than 5 years. And it was rugged. It could take a direct hit from an air-to-air missile and fly back to base.