You simply won't be able to afford them ..
Marines absolutely love it, they are the farthest onboard of any branch. I've seen no indication the Air Force wants to decrease their order.
I think the word "proof" is still lacking here.
AF needs more than 189 high altitude fighters which f35 never will be
They already have a very high altitude fighter, the F-15. If they need more, they can be bought. But at a whopping 110 mil each.
F15 is old...Not to mention we operate the oldest and least capable version in the world
You hinted we had none. Well, we do. And our F-15s have been upgraded till the cows come home. They still get first look/first shoot with every fighter except the F-22 and the F-35. And the F-15 can almost go into space and zoom to over 100,000 feet. The only one that can beat it is an old 60s bird, the Mig-25 for altitude. Can it fly at 60K, yes. Can it fly at 70K, yes. Can it fly at 80K, yes but the fuel and the pilots blood starts to boil.
Technically, we can build a jet to fly at 100,000 feet. But without a space suit, the pilot can't handle it. Hence the full pressure suits for the SR-71 pilots.
Besides, there is little to trying to fight above 40K. The air gets too thin, the engines start to starve for air, the pilots start having some serious health problems. Most fights are 20k and below since that is where the fighters will have the best performance. You keep looking at the paper performance. The actual performance is different.