But again, there are 300 + of the things already in service & upgraded (or being so). On my assumption that there really isn't an operationally valid reason (on the A-10, at least) for the second seat (remember, I've only said could, not should), that 'big enough cheque' can be spent keeping 'em in service for twenty odd years, instead.
Certainly, that cheque would be a lot smaller than the one written against a fleet of 'whatever' (and all associated costs therein), which may end up either sold off or in the boneyard before they've been amortised. I'm also quite sure that trying to replace the A-10 with the F-35 will be seen as pure folly soon enough, too.