The original plan for LAX's center was much more ambitious. Pereira and Luckman proposed a giant glass dome as the main terminal.[1] But each airline wanted their own terminal back then, and air conditioning that huge glassed volume was going to be a problem. So the central dome was downsized into the somewhat useless Theme Building. The center column, with restaurant, remained, but the arcs that suggest a dome structure seem to be decorative only.
The original architect's rendering shows a huge amount of empty floor space surrounding a central ring of ticket counters. It's not clear how they thought this would work. Huge queues at the ticket counters? People standing around waiting for their flight to be called, rather than waiting close to the gate?
It looks like they took their traffic flow model from train stations, where all the gates are close together and don't have their own waiting areas. Probably just as well that it wasn't built.
Really big airport terminal concourses remain a thing in China.[2] The empty space is underutilized, and much of it is used as a shopping mall. That's a Zaha Hadid design.
[1] https://neverwasmag.com/wp-content/uploads/2018/08/Pereira-a...
[2] https://mymodernmet.com/daxing-international-airport-zha/
