The problem with that is that it isn't the towns that are attacking our troops, it is relatively small groups of insurgents that are attacking from those towns. The average resident of those towns has a pretty limited ability to do something about relatively better armed and better trained insurgents, and we have often stepped back and left the Iraqi's on their own in the hopes that they would take care of some of these problems themselves.
We can't just level towns that are filled with mostly non-combatants. Striking at genuine military targets and incidentally killing some innocents is undesirable, but an unfortunate part of war when the enemy hides among non-combatants. However that is different than attacking a whole town simply because we know some enemy combatants are hiding there.
We are going to have to clear some insurgents out of populated areas, but that isn't how we are going to win the war. The Middle East is full of discontent youth that have been raised on hate and lies. Even if we keep killing insurgents, they will keep sending more as long as they have the resources to do so.
We need to take Iran out of the picture. We need to get those in Saudi Arabia that are also trying to create strife in Iraq to stop as well. How do we take Iran out of the picture? We attack them at home so they are too busy there to spend money and other resources waging war against us in Iraq.
If we can significantly cut down on the foreign money and foreign terrorists flowing into Iraq, then the Iraqis themselves can be much more effective at policing themselves. Those people in those towns might also start trusting their government or us enough to start reporting where the remaining insurgents are operating from within those towns, so we can take them out without killing large numbers of non-combatants.
Hell, these towns SHIELD the "insurgents". Look at the few polls of Iraqi citizens, they hate us. They LIKE seeing American Humvees blow up.
Bottom line, fight like WWII, win like WWII, fight like Vietnam, lose like Vietnam. It sounds to me like your strategy is what they teach military commanders from that war. If you'll recall, we came in second place there. We cannot afford to when dealing with islamunists.