"And I was telling you when you have things closer together like that, you suffer with future expansion. "

No, you don't. And for the THIRD time, I gave you real world examples of large airports where car to gate is only a few hundred feet. And as I ALREADY told you, a U-shape design allows for the shortest car-to-gate distance, with multiple concourses fanning out from the main U-shaped terminal. There is no more expansion limitation to that design than there is with the current airport. You seem to be having trouble visualizing what I'm talking about.

"I'm still puzzled as to why that's supposedly a bad thing"

Why would you be puzzled when I've already told you MULTIPLE TIMES, it's about efficient people movement. When you arrive at DIA you are typically at least 30 minutes away from your car. At DFW you are 10 minutes away. That might not matter to you because you don't travel very much. It does to me. You think this is the only design that allows expansion. Obviously it's not.