its a good system, but not for all.
Its not a hub and spoke mode--really a point to point.
They don't try to serve Wichita--more like ORD, LGA, MIA, etc.
AirTran has many things in common, but not all. Ex. no premium for one way.
EZjet prices are cheap if purchased far in advance, and then rise as the plane fills. Most passengers have bought their tickets weeks or more in advance. These are not business travelers.
They have figured out how to provide a service efficiently, even more so probably than SW and AirTran, and if someone did it here it would play havoc with inefficient carriers who fly the same routes.