Iraqi insistence that the 130,000 U.S. troops, starting last July 1st, largely remain on their 300 bases, has caused many American commanders to conclude that there's not really much need for a large U.S. force in Iraq. The enemy is not completely destroyed, and the Iraqi government is as corrupt and dysfunctional. But this is a common situation in this part of the world. It's a rough neighborhood. If the Iraqis don't want the Americans to help out, and Iraqis are pro-American (by local standards), U.S. troops, and commanders, are suggesting that they all depart as soon as possible. The Kurds are still very pro-American, and nearly all Iraqis are very hostile to Islamic terrorism. Mission accomplished.
This was always the plan. It is, in fact, the standard approach to these situations. Once the enemy is defeated, and a new (friendly, or at least less hostile and warlike) government is able to defend itself, you go home. After World War II, the U.S. kept troops in Japan and Germany long after the fighting stopped, only because there was a new enemy (communist dictatorships) next door. But the Iraqis are content to depend on U.S. forces based in Kuwait next door. The Kuwaitis are glad to have the American presence, because many Iraqis still believe that Kuwait should be part of Iraq. Iran threatens all the Arab states in the Persian Gulf area, which is why all those countries are eager to have an American presence, preferably just warships and aircraft. The Iranians are a threat, but not well armed. No one is expecting an Iranian blitzkrieg, but does believe that the Iranians will continue to make threats. Having some American troops in the way is seen as the best kind of insurance. The local Arabs were quite impressed at how the Americans deal with Saddam's army, and the subsequent Islamic terror campaign. The Iranians have a long reputation as good fighters, but the Americans should be able to handle them.
Getting out of Iraq quickly is something that is already happening. Every day, trucks and combat vehicles head for ports in Kuwait and Jordan, there to be shipped home, or to Afghanistan. Little of this equipment is being given to the Iraqis, who have their oil own money, and have been told to buy what they need. Another reason for not leaving a lot of stuff for the Iraqis, is because much of it would be stolen.
While Sunni Arab terrorists make the most noise, with their continued terror bombings, the real danger is risk of civil war between Kurds and Arabs. If the U.S. decided to intervene there, it would mostly require air power, as the Kurds can outfight the Arabs on the ground.
Within the next year, all but about 50 of those 300 bases will be evacuated by American troops, and turned over to the Iraqis. There will still be a lot of thieving going on here, but it doesn't pay to haul away structures and camp infrastructure. By the end of next year, there will be 50,000 American troops in Iraq, and may less. The job is done, and there is no point lingering.