That's a bummer. I think it is simply demand and then there is a limit to how many people can be out buddying in certain areas. My area must be the exact same.
Just a bit annoying trying to understand what order they are doing things in, if there is an order, people seem to waiting a very short time or a very long time, sometimes in the same area.
Very weird, even more annoying when you see a van kicking about.