Why hub-and-spoke transport never disappears

Why does hub-and-spoke flying persist when point-to-point routes are available?

Small destinations still need regional aggregation, while only routes with enough demand can support direct point-to-point service.

Many small airports cannot sustain direct service to every distant destination. A regional hub collects those thinner flows and connects them to trunk routes, much as local roads feed motorways and branch railways feed larger junctions. Denser and more capable networks allow major city pairs to gain direct flights that bypass the hub. That growth reduces some connecting traffic without eliminating the underlying need for aggregation. Mature transport systems therefore combine point-to-point links with persistent hub-and-spoke structure.