The war and subsequent insurgency has destroyed much more infrastructure than we were able to build. When we leave, Iraq will be a shadow of its former self, it will go from a credible counter to Iran to an Afghanistan-type shatterbelt of tribal fiefdoms. If we leave any equipment, it will be because we left it for the government we leave in charge, just like the Vietnamese used our helicopters and howitzers to wage war successfully on the Chinese and Pol Pot. But they'll be cannibalizing our wrecked Humvees and Bradleys for spare parts and scrap metal for decades to come. The only thing they won't use are our rifles. Kalashnikovs are a superior product.