An Apache battalion is 24 aircraft, 8 per line company. The cavalary still uses the troop and squadron organization, while a regiment is composed of multiple battalions. It takes a battalion (24) worth of aircraft to keep an aerial weapons team (AWT), a flight of 2, airborne 24/7. That's what you need for on call CAS, the sector size predicated on FARP's because you need to have good station time. The next issue is sustainability because a year of that is going to put 40,000+ flight hours on the battalion so aircraft are going to start going down for extended periods for reset (measured in months) and the people are going to need a reset as well.
Unlike a case of rifles, attack aircraft aren't something you can just give to an ally and expect them to be able to use, it takes years of training under the best of circumstances and Iraq isn't best of circumstances. No question, they can't beat IS/ISIS on their own and neither can airpower alone.