Unfortunately the sacrifices to make the Marines version effected the design of a and C. To scrap b, would be crummy design with out the benefit. Tyler wrote about that a while ago.

At the start of the current war, we could have made a fairly inexpensive a-10 2.0, used it for the past almost 20 years and abandoned it on the ANA and Iraq army. It didn’t have to be something awesome, just a decently powerful plane for cas, a better cannon and ammo suited for shooting pick ups not tanks. Upgraded…