For me there's a very simple correlation between the demise of small flying schools/clubs and the rise of the large commercial flying academies, universities and airline cadetship programs.
There was a time when every school/club in the country always had a few students sitting around building hours towards their CPL. That used to be the backbone of many of the schools/clubs. Now that business has moved on and the only training to be done is for recreational purposes. I think this move towards purely recreational training has also contributed to the rise in RAA.