There's nothing particularly magical about IED's - they're glorified land mines. They're the modern equivalent of the ancient technique of digging concealed pits with sharpened stakes at the bottom. The Sunnis can't win the war using IED's against Shiites because the Shiites - in the absence of Uncle Sam's restraining presence - will simply kill everyone and destroy every structure within some distance of the IED. This kind of strategy has worked in every military campaign in which it has been deployed. We are too squeamish to use it because we are Americans. I guarantee you that Iraqi Shiites don't share our moral qualms.
Have either of you ever been in combat?