A simple fighter plane will allow the US Air Force to purchase more, several times more simple fighter plane.
A simple fighter plane will reduce the time from conception to development to production to deployment.
But in the unspoken view of the US Air Force.
A simple fighter plane will be a dumb and cheap and small program that no Air Force personnel will dare touch because dumb and cheap and small programs does not build legends for which to build one's career.
A simple fighter plane will be unsexy and, thusly, unattractive to fighter pilots. I'll wager that pilots tasked to fly cargo planes will not want to be flying a simple fighter plane too.
Then, again, pragmatically speaking, deploying more simple fighter planes will require the training of more simple fighter plane pilots and the US Air Force has had difficulty, several decades now, in attracting qualified recruits to train for fighter pilots. Even if the US Air Force lowers its requirements it will, in all probability, still fail to seat a pilot in all those simple fighter planes
Once trained, qualified, experienced, the US Air Force will often see these seasoned fighter pilot leave, after completion of their tour of duty, to join the ranks of commercial pilots, a much more lucrative proposition for the pilots. The US Air Force simply cannot afford to match the money offered by airlines to the pilots.
I recall when the US airline industry was deregulated and subsequent fare reduction led to airline expansion leading to a dearth of well-trained, experienced pilots. Until, that is, the US airlines discovered the US Air Force's treasure trove of well-trained, experienced pilots.
So, what does the US Air Force do to retain this expensively trained fighter pilots?
Yes, build sexier fighter planes.