At a single organization level, there will always be lean years or not. It also has a lot to do with individual dynamics - the one or two people with that ability to engage people, get them motivated, or just make it fun can change a group so much.
I do think the concept of giving (as in giving for the sake of giving) has gotten a bit tarnished, though. Another issue especially for the type of activity you describe, is people, I think, are much less able to successfully socially interact with strangers, people outside their immediate circle.