What a load of horsesh....(you know the rest)!
If an airport has no other way of making money other than through aeronautical charges such as landing fee and PSC, then this is where they will find the money to build new customs facilities. This will result in higher costs for airline, high fares & less passengers!
Airports need to increase non-aeronautical revenue through retail commissions, from shops, car hire and restaurants etc. This should mean they can reduce PSC charges and landing fees.
The result being, lower charges to airlines, low airfares, more pax to through the airport, and so on and so forth!
Any questions?