Iraq has no proper air force so the US fills that in.
Either way the USAF doesn't support the ISF as much as it supports Kurds or it's own ground troops, in 2004 they used a lot more and heavier bombs on Fallujah fighting a weaker enemy though using a lot more Abrams tanks.. yet they took 2 weeks longer to take the city. I know you will find a way to reject how effective this OP was but i'm quite sure the coalition generals who have been watching know, their opinion matters not someone on a forum.