Actually I'd say the blame for the impending A-10 retirement rests not with the USAF, but with Congress. Or, more specifically, with the Sequester that Congress forced upon the military. Everything I've heard from the USAF on this issue states that they'd love to keep the A-10, but that the only way to do so while their budget is being cut would be to sacrifice other aircraft that they deem are more critical, such as the F-35. And frankly, for our future military, the F-35 is more critical. If we want to stay competitive in the air in the coming decades, we'll eventually need to replace our aging F-16s and F-18s, and the F-35 is now the only realistic option for doing so. The A-10 is great for low intensity COIN, but it's just not built for the realities of modern high intensity conflict.