Incompetent and poorly maintained Iraqi Air Defenses are hardly a qualifier when compared to actually competent trained crews manning modern air defense systems. The armor on the A-10 is designed to protect it against flak, not missiles. It was well established by the Air Force that in the event of a conflict with a peer opponent fielding modern SAMs that the A-10 would've suffered very heavy losses.
OK, let me remind you again the A-10 combat losses since the aircraft was introduced. I know I already said this once before.
The actual number that have been shot down is 4.
In April 2003 one was shot down over Iraq by a German made ROLAND missile. That is the only loss since 1991.
In the Gulf War we lost 3. February 2 1991 one was lost to an SA-16. February 15 two were lost the SA-13.
Side note, we did loose an additional 4 OA-10 jets, all in 1991. Two to groundfire on February 15. One shot down by an SA-9 on February 19. The last on 27 February by an unknown missile. But as the name suggests, those were primarily Observation aircraft, attack was a secondary role.
That makes a total of 8, actually a rather low number considering all of the conflicts they have been in.
And you apparently do not understand the role of the A-10 in a battlespace.
A land-air battle has 3 main areas. The one that is the most risky is the ones that operate behind enemy lines. This is the location that they are most likely to come under ground fire. In areas like this it is not the role of the A-10 to take operate, this is the realm of air to air fighters if there is no air superiority, or fast moving air to ground capable fighters, to eliminate such threats.
Then you have the FEBA, or Forward Edge of Battle Area. This is where the enemies are actively fighting. There is a risk here, but that is primarily MANPAD type systems, and conventional Anti-Aircraft Artillery like the ZU-23. The more powerful AA missiles are already going to be roadmarching their equipment and pulling back if they are in this area, because they are highly vulnerable to targeted artillery or even fast moving columns of ground forces.
Then you have the battle area itself, and the area right behind it where stragglers might be found. Also this is the area of MANPAD and conventional AA. And AA missile systems caught here are likely being prepared for destruction, in the event the unit is overrun by land forces.
Oh, and the armor is armor. It is designed primarily to protect the pilot and the cockpit. The aircraft is designed to be able to take a lot of damage, and that is on purpose. An A-10 can loose half of a wing, half of it's tail control surfaces, 1 of it's 2 engines, and loose half of it's control systems and
still be able to return to base. And in reality, AAA is far more of a risk to them than missiles. Missiles do relatively little damage to one because of proximity fuses and their using essentially shotgun effect to destroy control systems (like hydraulic lines in most aircraft). Because the A-10 had redundant hydraulic and wire control systems, this is less of a threat.
And missiles are generally not fired more than 2 at a time at most, with a smart missile operator launching no more than 1/8 to 1/4 of their available missiles, less the A-10 be a decoy for some faster moving aircraft armed with HARM intending to take it out while it is bingo on missiles.
But first, let me school you in some accurate terminology. SAM is used to refer to conventional ground to air missiles, like the SA-9 or SA-13. MANPAD is the term for light weight missiles either fired directly by a human, or in the hybrid systems that mount those missiles on a vehicle (like the US AVENGER system). And because the A-10 does not generally operate forward of the battle area, this is a very low threat. In fact, any missile crew if given the choice between an A-10 as a target and an F-16 as the target are going to go for the A-10 every time. They know how resistant the A-10 is to fire, and the fast moving F-16 is much more of a threat both to themselves as well as to their fighters trying to keep them away.