F 35 developed to replace f16, f15e, A10 for USAF, Harriers for USMC and a naval version for usn.
USAF consider b52 for some A10 role, and now a new 4.5 gen for replacing some f16.
Usn giving more importance to F18SH and NextGen. Only USMC happy with f35b.
Maintenance is the biggest issue...