Your thesis is somewhat out of date LLamaFarmer.
Both Ryanair and Easyjet have moved into the primary city point to point businesses often head to head.
From UK provincial cities especially - Combined they serve a wide range of major city pairs across Europe - more so than the heady days of BA Regional operations !
Now I may say that some of the so-called secondary airports that gave Ryanair a tag line were/are often closer more convenient and easier to use - Rome Ciampino for instance.