HOA Board/Committee Volunteering

I noticed during the last few weeks that HOA Board/Committee volunteering is a good example of Prisoner's Dilemma in a sequential format. Due to some criminal incidents lately, HOA Board of my community decided to establish a Security Committee and asked for help. I was one of the 6 volunteers to work in this committee. We met few times and decided on actions to take. Recently few members stopped supporting the committee. As a result, I have immediately seen an increase in my responsibilities (worse payoff due to more time/effort spent). So some of the players "cheated" causing a worse payoff for "self" while they received higher payoffs. It was because remaining committee members took care of the duties anyways and "cheaters" enjoyed"better payoff" due to less time spent on the matters. Because we are the owners of the houses and we will be playing this and other games with those players again, they will have a bad reputation and will not potentially be trusted in the future.

I created the following simplified sequential game tree where all the players other than "self" were considered to be a single player (called "them") to simplify the game structure. Two strategic moves for each player are (Contribute or not). There is a single nash-equilibrium of (Not contribute, not contribute):

However, collectively as a community, if we could have recruited more volunteers, everyone would be better off. Total payoff would be largest for the society while individual payoff would be reasonably good (5 for self and 5 for them).

In general, most volunteering situations can be considered to be a "Prisoner's Dilemma" type of game. They can also be modelled as simultaneous games.