Incorrect.
The A-10 was used in combat for the first time during the Gulf War in 1991, destroying more than 900 Iraqi tanks, 2,000 other military vehicles and 1,200 artillery pieces, making it by far the most effective aircraft of the war.[5] A-10s also shot down two Iraqi helicopters with the GAU-8 cannon.
Yes, because the Iraqi military had literally no air force. There were a couple of dog fights throughout the entire war, but the Allies had air superiority nearly the entire time. When you've got air superiority, the A-10 is a great jet. But when the enemy is organised, has AAA and an air force worth a damn, the A-10 is in trouble. It's slow, it's not stealthy, and despite being more armoured than an F-16, it cannot withstand heavy AAA fire. It's like the AC-130, cool as hell but only if you're not going to get shot at.
It was designed for European battlefields in the cold war, a scenario that is no longer relevant anywhere around the world, and even in that scenario it was expected to get shot down regularly.