Biggus... you should know that aircraft get more expensive to maintain as they get older... and even new-build Super Hornets will be maintenance pigs in another 20 years... while the F-35s, having newer systems, should theoretically be cheaper to keep flying.
Planes at age are older to maintain, that has basically always been true, the idea that the F35 differs from that is substantiated by exactly nothing, certainly not by what has been claimed about it theoretically.
One of the main arguments it had going for it at its conception was that it was going to be no more expensive than the planes, like the F16 F18 and Harrier, it was to replace.
A promise which it broke on almost all accounts, maintenance will be no more different IMHO.