And the A-10 was built before the MANPAD threat become serious. Sneak in at treetop level against gunners in turrets and you very well might be able to get in and get out in reasonable safety. Now, you'll be getting out with a missile (or maybe even more--the response will not be coordinated, those who have a launcher and a shot will take it) on your tail--it can't be evaded, you have to decoy it or blind it.