The US Air Force design program is laughably bad - it would be more so if it wasn't our tax dollars being pissed away.
The same thing happened in the past to the B-1 and B-2 bomber projects, which cost $200m and $700m per unit respectively. Massive scope creep leads to huge unit cost inflation, followed by a reduction in number of units ordered to keep total cost below the Congressional mandate for the project. The low number of total units ordered leads to an increase in maintenance cost per unit, which eventually leads to shortening the plane's lifespan (too expensive to maintain, each airframe receives double the hours it was intended to endure).
Compare the F22 (at 150m) to the F16 (at 10m). Aside from the stealth capability, this jet is not 10x better than the F16.
While I agree with your overall point, the cost of a new F-16 these days is more like 40-60 million USD, not 10 million.
The cheapest 'good' 4th-generation fighter is the Saab Gripen, which was designed in a single country to intentionally-limited specs, but even those cost 30 million USD a pop for the standard C & D models and even more for the NG units under development.
To some extent modern fighter aircraft are inherently expensive as a result of all the technology that has to be crammed inside them. They're multi-role networked flying systems these days.
In essence that's part of what has derailed the F-35. Technological advances have allowed for the extensive use of software to create capabilities that just could not have existed before now, such as the ability to see 'through' the plane, an extremely high level of sensor fusion and integrated systems, etc. But massive software projects are inherently risky and can fail massively if not managed very carefully. They've been doing things with software in the F-35 that have never been done before in this context, which only increased the risk.
Also do not underestimate the costs of redesigns following the theft of F-35 design information by China from both Lockheed-Martin and Pentagon computers. I doubt that's the sole cause of the cost overruns, but it definitely hasn't helped.
The same thing happened in the past to the B-1 and B-2 bomber projects, which cost $200m and $700m per unit respectively. Massive scope creep leads to huge unit cost inflation, followed by a reduction in number of units ordered to keep total cost below the Congressional mandate for the project. The low number of total units ordered leads to an increase in maintenance cost per unit, which eventually leads to shortening the plane's lifespan (too expensive to maintain, each airframe receives double the hours it was intended to endure).
Compare the F22 (at 150m) to the F16 (at 10m). Aside from the stealth capability, this jet is not 10x better than the F16.