I believe that @WestRiverrat pretty much hit it on the head. An A-10 Warthog has a titanium bathtub for a cockpit and can remain airborne with a surprising portion of the plane shot off whereas most helicopters can be taken down by small arms fire and even the toughest can’t compare. Considering that they move so much slower than jets, they are more likely to get hit as well; More hits plus less ability to take hits equals poor survivability.
Besides, nothing says “Bend over!” like seven barrels spewing large caliber depleted uranium slugs so quickly that they are almost nose to tail. Yeah, rockets are neat, but a GAU-8 Avenger will really fuck up someone’s day.
@Riggerman Yes, they can, but the real trick is making it back for a landing ;)
Other than that, you are right though.