You know damn well this isn't how it works. Some head coaches come from a defensive background, others come from an offensive background. Whichever one it is, they generally oversee that side of the ball and the other is left more under the control of the coordinator. This is how it works throughout the league. Also, one unit is pretty much half the game (a little less, but they've been consistently excellent on special teams too), so being elite on one whole freaking side of the ball is pretty damn impactful and important. this is also a league that's built for parity. you can be balanced or you can be heavy on one side of the ball. the bears have chosen to put most of their resources into their defense and they've been successful doing that, and lovie has been the architect.