F-35, I would say easily YES. Since we are planning on buying so many, the R & D costs will be spread over so many aircraft, their price will be similar to buying a new F-16, except that it's a whole generation better than the F-16! By the time you remove and replace stuff on a plane that small, you can just about build a newer better version.
F-22 can be argued. There's obviously a lot about what it can do that we can't talk about but I'm sure plays a lot into the decision making. Other countries are starting to catch up in terms of what the Eagle can do, so in order to stay ahead in the Air Superiority game, here comes the F-22.
In general, for any fighter, at the time we started purchasing F-15's and F-16's, no one in their right mind thought we'd be flying with them with as many hours as the already have. 18+ years of flying in the Persian gulf area haven't helped any either.
More important than plane hours and costs, I think the AF needs to start paying more attention to pilot manning and retention. What I saw growing up in a Viper squadron from 2002-6, the only NVG IPs we had at Aviano were the squadron CC and the weapons officer! How do you do upgrades w/ experience levels that low? Most of the problem was so many dudes (like me at the time) were showing up from the B course as a new wingman instead of other flight leads and IPs w/ experience. So, in order to create experience, we had some rather large flying hour programs. But the AF is still turning dudes away from TX opportunities b/c there are too many guys in the B course... Kind of a Catch-22 which won't get any better w/ Luke downsizing... I know it's currently happening at Shaw w/ dudes having to go on instrument sorties single ship b/c there are no flight leads and too many wingman.