Paintball had a peak in the mid-2000s (I would say 2006) due to a combination of:

- Millenials who were kids of the baby boomers being in their late teens early 20s

- Disposable income due to the real estate bubble / positive consumer sentiment

It dropped off a lot after the 2008 GFC though.

BUT

A lot of those kids playing in the mid 2000s are now parents of ~10 year olds so apparently there is a bit of a resurgence going on.