My working theory is that Lockheed got so mad after the F-22 was cancelled after 187 planes (and they missed out on millions in sales) that they decided to recoup their losses with the overruns on the F-35.
Time is gonna have to tell but planes designed to be the do-all-end-all planes usually aren’t.
It's probably closer to the truth that Lockheed Martin was hip deep in the F-35 program and didn't fight very hard to keep the F-22 production line open past the 187 buy. Had Boeing won the JSF competition, L-M would have lobbied congress much harder to purchase more F-22s.
With any complicated system, the more you ask it to do the less well it will do it.
A small, prop driven, COIN bomber would be great. The F35 would be horrible at that role.
Not to mention the risks to losses. Losing a few F35’s would mean we pull them out of the theater. Quantity has a quality all its own.