Costs and charges are NOT the issue or the prime cause of the flying hours for private/business falling.
For the first time in my 40 years in this business, many pilots are packing up and going to do something else in their spare time and it not the costs that are driving that change.
Certainly the cost increases brought about by "user pays" does not help, but the main reason for pilots leaving these days is the never ending changes to rules and procedures (14 years of airspace changes is just too much for some!), the increased complexity of the rules (not simplification), changes that make no sense, like the new pilot licences, the increased profile of the punitive measures and the attitude that many see CASA now as the jack-booted policeman, not as an organisation that is here to help. Flying once upon a time was fun. Those days are gone and it is going to get worse under the new security proposals.
It would really help if we had a government that supported an aviation industry and infrastructure. We don't so don't' hold your breath for any improvements anytime soon!
Can you really blame those that now go and fly a U/L or sail a boat?
Dick's graph is interesting, but only tells part of the story. And it has nothing whatsoever to do with NAS.
NAS is driving people out of the industry, not keeping them in or making it attractive to stay.