I have no doubt that the joint concept doesn't really save any money. Complexity is complexity, I just get bothered when people go on about how this thing is way too expensive, well compared to what? The first actual F-35 flight was in 2006, everything before that was prototype DARPA type shit. So we're less than 10 years of the real aircraft, so really about on par with the F-22. It's a shit load longer than I'd like to see, but it seems to be standard for the industry.
If my google foo is ok the last super hornet buy has a fly away cost about 60mil per bird, I picked that aircraft because it's the newest fighter the DOD has bought in awhile. The flyaway cost for the F-35 is about 80mil if you buy the forecasts for 2018. So the new hotness is about a 30% cost increase. All the LRIP costs are floating all over the place, in my opinion part of the rush to kill other platforms and ramp up F-35 production is to prevent a cost spiral. So there is no doubt that the new jet costs a lot more than the old stuff, but is that worth it? What would the cost be to upgrade the super hornet class of jets to F-35 class avionics? Since the F-35 avionics are a large part of what's holding things back, I don't see how a block XX F-16 with F-35 type avionics doesn't close that gap pretty significantly as well as eat up time. So we might end up with a badass F-16, it'll still have a worse RCS, inferior performance when loaded for attack, and it will be just as shitty for low slow escort, the single advantage of the F-16 is last ditch survivability, it can jettison all the extra weight and turn itself into a BFM monster. When has that been a key player in the last 20 years?
As far as the F-35 replacing the A-10, fast movers have been doing CAS for a long time. The marines have been doing it without the advantage of the A-10 for awhile. The biggest problem is the AF will try to multirole the shit out of everything without realizing the biggest reason A-10 squadrons are really fucking good at CAS is because that's what they do. This is more a pink body issue than platform issue. When the F-35 really comes online, the AF needs to not have a blanket DOC statement for all F-35 squadrons, they need to specialize. As far as the A-10 specialty of low slow escort, well we're fucked, we (the slow fat kids)need to take that upon ourselves.