Originally Posted by
procede
@notapilot15
I did not misread. One super hub with the same traffic as two smaller hubs is twice as effective as the two smaller hubs, as if offers twice as many possible connections.
The main issue is effectively using runway capacity. On some routes an RJ might suffice, on some others having an A380 instead of two A330's basically means you can add an RJ or 737 with the same (limited) runway capacity.
Atlanta has had a single A380 flight from Qatar, but then ATL is not (really) runway capacity limited. Availability of gates is a more important issue, especially as they have only one that can handle an A380:
Busiest airport can't give biggest airliner a gate - CNN.com
From a hypothetical mathematical point of view one super-hub looks attractive. However, from a real world point of view it is not really that sensible. Geography must be considered - you would not close Seattle and have all interchange traffic instead sent to Atlanta. There is obviously a distance that needs to be considered.
As important is the fragility of a system where a ground-stop due severe weather at a single hub can bring the almost the entire system to a halt.