“It would be cheaper and easier to get more SU-25s which are the Russian equivalent of the A-10.”
That’s true. Except, the USAF does not have any SU-25’s lying around but they do have a plane they’d really like to get rid of. Also, if there were any SU-25’s in play I’d think Ukraine would be on it in a heartbeat. But, like the kid with a rich uncle, the Ukrainians will hoover up anything Sam is willing to let go of.
Other countries do have SU25s they could supply. A-10s would be a truly bad idea in that war - without the latest upgrades, all of which are dependent on US comm systems and are classified. Stripped of those - its suicide.
Besides we will need then later in some future event. The F35 cannot replace it and neither can the Toucans.