i'm sure a lot of good learning came from the F35 - people forget that this is just a massive R&D project, and that isn't cheap, its incredibly expensive. You just don't "build" jets the way you build a car, and as tech gets more advanced, it becomes more difficult to squeeze out gains. If Lockheed is organized well, any lessons and experienced they gain from the F35 (either technical breakthroughs,FMEA style knowledge, operational knowledge, etc.) filter into its other existing projects.
Edit: of course, sans corruption via 1000 dollar toilets. I'm thinking of people designing, building, testing, gathering data, and filtering it back.