So you want the US to bombs fortified targets on a tactical level to soften them up for infantry and armor. Which is combined arms. Which is what the US already does.
You are very stupid. You destroy cities (which is not tactical at all btw), then go in to mop up without giving a f*ck about accidentally killing civilians. If it looks like a terrorist, you shoot it. And the cost part: 1 month of a shitload of bombs is better than 5+ years