Model is broken
Hub and spoke is broken, because it's designed incorrectly. Think of how a typical computer network functions with edge and core routers. Now compare that to the airport model: all the "core" components are also your biggest "edge" components.
In an ideal world we'd have a few massive "core" airports that have no* security gates, no* baggage carousels, no taxi stands, etc. They would be located remotely from large cities in order to have plenty of runways and plenty of clear land around them (no noise abatement restrictions). These would have plenty of short hop flights (or possibly regional rail) to smaller airports located in population centers.
It's an idealized scenario that probably cannot be realized (especially in a competitive airline market)
* (or extremely minimal)