The vast majority of human traffic is comprised of travelers - who need to get to terminals/gates through three (but going to be two when the A terminal walkover bridge closes) choke points. It's the TSA security theater/cluster contributing to the delays. Get people into the terminals, and if you really want to whiz away money on a construction project, build some walkways/escalators to let people travel between terminals outside of the train system. People don't have time to dink around outside of the terminals at DIA, that is just stupid to think otherwise, obvious to the casual observer when viewing the Disneyland-like lines on Sunday mornings. Some other airports have more dining options on the outside, but that's mainly due to the lack of options in the gate area. I would never, ever plan on eating outside the terminal area at DIA due to the high variability in screening time, even with pre-check status.