High performance dogfighting fighters are out of favour amidst the USAF generals. This is why the F-15 remains without replacement (at 183 minus a few attrition F-22 losses there are not enough of them for the task), no new light fighter F-16 replacement either, but lots of long range AG strike platforms.
That's how it is, for the moment. it'll take a few F-15 AA losses to wake the USAF up. The navy is not asleep though: