As I understand it, the original USAF plan was to buy enough F-22's (i.e. replace F-15's near one for one) so that the F-35 could happily be a bomb truck that could just defend itself to some extent.
With the F-22 order slashed and the USAF still flying lots of F-15s to make up the numbers it does seem the F-35 will have to take up the slack in Air Superiority by default.
I doubt Lockheed envisioned that the F-16 replacement would also have to be an F-15 replacement also!
I think they need some Typhoons to help out the F-22's in A2A?