Having air superiority and having manned fighter planes is not the same thing. Air superiority is a must, but piloted-fighters are not the only way to achieve it and as technology advances, not the best way to achieve it.
There is less and less need for a human in the cockpit. In many cases, the human only limits the weapon. Technology is not yet in a state where the human is completely redundant though. In addition, if you rely completely on AI and/or remote controls, you run the very serious risk of being annihilated by electronic warfare (EW) measures that you did not predict.
The current situation is that the bulk of airborn combat missions are shifted toward the use of drones and manned planes are pushed to "complementary" or backup status. Therefore there is not need to maintain a very large and expensive fleet of fighters, nor to develop new planes, as long as upgrades to the current fighters are sufficient to keep up with the competition (that is not clear who the intended enemy is exactly).