Most supersonic fighters can only do so for very short amounts of time. The F-22 is the only operational fighter with real sustained supersonic capabilities.
The difference between the F-18 and the F-35 is that while the F-18 might need extended maintenance after prolonged (read : more than a minute) supersonic flight, the F-35 may suffer catastrophic coating degradation that may be fatal in the same flight.
As for other operational fighters, the Dassault Rafale can supercruise indefinitely the Gripen indefinitely at Mach 1.3, the Eurofighter indefinitely at Mach 1.8, the Sukhoi-35 can if outfitted with the AL-41F-1S (meaning, some operational Su-35s can supercruise indefinitely, but not all). The F-22 is far from the only one.
If you need a fighter to fly 500 km and engage a target, why wait 25 minutes for a super-cruising mach-1 fighter when a Mach-2.3 craft without super cruise can get there in 10 minutes?
Can’t the Eurofighter Typhoon supercruise?
From an engineering perspective local political optimization of a national project is what I would call ineptitude. But you can call it by another name.
Which is another area where F-35 is lacking: range. Without external fuel tanks it can't fight in the Pacific.
If only we had large floating aircraft bases and the plane also had versions that supported VTOL for even more expansive capabilities at sea.
If you're going to base your availability of air power, which is the main determinant of success given the American military doctrine, on having a secure and available carrier at all times, you may be putting yourself in a bind when anti-ship weapons start proliferating and you become forced to increase distance between those defenses and your carriers.
It also puts a hell of a single point of failure.
The best thing that could be done would be to have enough range to be able to fly out from a carrier that's relatively safe from antiship missiles. But that may well become impossible anyways as antiship missile evolve.