P-40 was obsolete and continued production of it was actually brought up in trials post-war to see if corruption and bribery were the reason it was so prolific. That's not a good example to use for "numbers are everything" -- because they aren't.
P.S. The F-15 would cost more than the F-35 at a fraction of the capability. assuming the fuselage didn't crumple between the cockpit and the intakes like several have already begun to do.
The airplane was available in large numbers and it did the job worldwide. The F-15 is not an ideal comparison because it is actually better on a relative basis.
Learn some facts. The reason the fuselage is breaking is because they're ancient. They need to be replaced. Same with the F-16. They're being held together with bailing wire.
The Marines are suffering because they won't buy Supers. Gotta hold onto their VTOL fantasy. As a result, Marines are being killed because the Classic Hornet fleet is falling apart.
Capability? What can the T/A-35 do that an F-15 can't? Oh, yeah, get shwacked by the Su-27, PAK-FA, or some random Chinese J-xx.
Cost? The Just So Failed is gonna' cost at least double what an F-15 would (and I'm being generous) for no capability or performance whatsoever.
The F-15 gives you options. The T/A-35 doesn't.