Womp womp
I have a very bold suggestion: one F-35 for one FC-31 trade. Seems like a fair trade to me, US need an air combat focused stealth fighter and PLAN could use some VTOL stealth attack aircraft for 075/076, it's win win!
Its much better to directly read what USAF chief has said, which is what David opined on.
According to him, there is necessity of a newer fighter *not* because of a deficiency in F35 (capability vis-a-vis platform), but because of the deficiency of numbers of F35 due to its slower production on-ramp (about 6 years), as well as the F16 units in ANG that need a replacement or costly MLU within next 5-10 years.
That's why he also talks about rationing the flight hours of the existent and upcoming F35 airframes, using his 'ferrari' analogy.
One could argue they could just increase the intake of F35 in upcoming years to make up for the shortfall, but the cost penalties stand against them, since there's an upper limit on basing, training and maintenance capabilities of underlying program structure.
What they want to buy is not something that replaces the F35, but something that is a notch lower in terms of capabilities to cover all the missions that don't necessarily require cutting edge tech.(Middle east comes to mind), while still having the quick adaptability that is inherent in the newer digitally maintained jets.(in terms of weapon, subsystem integration and various comms, syatem upgrades)