This is where I disagree. We are totally capable of it, but we lack the will because we don't want to deal with the collateral damage that is inherent with a "real" offensive. We could start by flattening Raqqa, which would kill thousands of innocent people along with a lot of IS fighters, then spend several weeks or months just destroying anything that goes outside or gets in a vehicle in IS held areas. What we're doing now absolutely will not work, because we are just going after militants when they attempt to advance. We're effectively just hitting the pause button on their advance. To actually win, we have to make it an environment so horrific that the people of the area, including IS, will do anything just to make the suffering stop.