Phillip,
A few years ago, Toro told me they mailed out just over 400 of their product brochures to different architects. They mail to associates they know, or who are in ASGCA. The number of firms back then might have hit 300 at the peak, but probably just under. If you were talking about individuals at all levels in all firms, there might have been 500 people actively involved in gca.
Everyone is cutting back. The number of associates is way down. How far down? Well, we have shipped so many drafting jobs to India that they now want a sub chapter of ASGCA!
Even the big boys have laid off several or are contemplating it if "industry sources" are correct. My firm is now either three (me, myself and I) or 4 if you count my CAD software.
I am having the time of my life learning to draw a new way.