Ira,
I can't answer your question factually. I was surprised at the PGA show to learn that according to NGF, last year was the first time the statement "Golf is cool" had a higher positive response from those under 35 than those over 55. That might not translate to reduced senior participation, and I tend to agree with you that seniors continue to play longer in many cases. And, many clubs have adopted a philosophy of maximizing their enjoyment of the facility as long as possible, with additional tees being a main tool.