Those are municipal boundary figures: nevertheless, you don't have to be a genius to realise that these cities will have substantial draw from the hinterland and the total available market will probably be double the base figure.
What you have to be careful of is overlap: for example, London and Birmingham have a certain degree of overlap in catchment area as do Dortmund, Essen, Koln and Dusseldorf.
Equally, Manchester which isn't on the list has LPL, FR Base, just down the road.
In simple terms though you can see that availability of new territory is reducing.
Of course, the other very valid points you have made( to the vast majority of cogent individuals) don't stand up when you look at certain FR destinations, Torp, Beauvais, Knock, Valadollid, Hahn, Billund, Vasteras, Skavsta and the French beyond the back of beyond airports.
Never assume you are dealing with a sensible mind
