Volunteer numbers are down where I patrol.
I can see why. It's a big time commitment, not just the days you could be free skiing, but instead are patrolling, also the time spent taking the first aid course and re-certifying exams in first aid and on-snow. If people want to give something as a means of charity, it's a lot easier to just write a checque out to whatever charitable organization they prefer than to donate their time.
There may be a very limited number of folk who can't afford a ski pass who do it so they can ski, but I'm sure that number is very low.
I do it because I find that means of charity agrees with my abilities and the fact that I like helping people. I remember when I was first asked to join patrol quite a few years ago, I thought, "Well if I come across someone wrapped around a tree, I'll be stopping to help him anyway, so I may as well learn how to do it right."
I see two main sources of ski patrollers, those who came into it due to them being skiers, and those who came into it due to them being medics of one sort or another.
The City I patrol for has a relatively good deal for patrollers, but it's still not worth giving up my time for what they offer.
People who haven't done it think it's all about free skiing, but it's not; it's work, with responsibility, stress and risk.