Over the life-cycle time of 50 years operating a fleet of F-16 is not going to be noticeable cheaper than operating F-35s. Initial acquisition costs is only a minute part of the overall cost of operating modern combat aircraft.
My country, a small country with just five million people, are buying 50+ F-35s. Our current similarly sized fleet of F-16s needs replacing. No matter what we do our F-16s will be ending their service life in the next 15 years. The F-16s will be phased out, gradually being replaced by F-35s. If the acquisition cost of the F-35 increases, it will simply just extend the replacement timespan.
If a tiny country like Norway can buy 50 of these jets within our tiny military budget... What's the problem for the mighty USAF/USN?