Use of AC-130s requires a very permissive air environment. We wouldn't have that at first, when the tank columns need to be stopped. The A-10 is somewhat vulnerable, but it can run and hide among the tree tops, which the Spectre/Spooky can't. Even in Vietnam the older models required fighter escorts, and that was a more permissive environment, mostly, than you'd have the Backyard of the Bear.
They work at night now and most are in Afghan. Iraq needs us less and less now. The electronic counter-measures now can blind most radar systems. New ones are being built to replace ones taken out of service. I know because of the serial numbers of the 3 ground-mapping radars I work on. Their fire control radar is maintained by some avionics squadrons.