F-15 EX is a 80s fighter , it have zero stealth capacity to penetrate a high end theater, the F-35 have no supercruise and a poor top speed of 1.6 and a 50000 ft ceillingcapacity not realy enough to match a SU-57 or a J-20 in air-air fight, the F22 is the right plane but there is just 120 of them and need to be retrofit. NGAD is realy the capacity needed for the near futur, China is running realy fast and with this strategy the first 6th gen will be Chinese. Another capacity in danger in USA is the hypersonic too for instance Russia and China match the US capacity, so it is time to wake up USAF if you want to be the first force in the air.