There is speculation that the Army would take the A-10s, but it just isn’t going to happen. The Army is divesting itself of all sorts of stuff – Kiowa Warrior helicopters, tens of thousands of troops, etc – to meet its budget pressures, and the chances of the Army finding a few billion under the seat cushions to take control of A-10s is zero.
However, it is certainly known that weapons systems unwanted by one military service can find their way into other services. For example, the Army decided a few years back that it didn’t really want the C-27 Joint Cargo Aircraft that it had already bought, so they got transferred to the Air Force. Then the Air Force decided they didn’t want the planes either, so most of them are being retired but a few may find their way to the Coast Guard.
Another example is that the Army started buying Joint High Speed Vessels, then it decided it didn’t want to be in the ship business anymore, so they boats were transferred to the Navy.
Both examples happened just within the last few years. I’m sure if you turn back the clock further you could find many more examples.
(Do you notice a pattern of the Army buying stuff that it soon decides that it no longer wants?)