Some continue to serve because they think no one else will. Interestingly enough, if there is never a void, there will never be a need to fill it. Fresh blood is needed to keep the Board revitalized. Consider term limitation as a way of forcing the issue.
Money is the lifeblood of the organization and without it, the assets wither and deteriorate.
Inability to collect money is a common symptom of communities doing in house bookkeeping. Let's face it, collecting debts from neighbors is hard and many board treasurers tend to avoid confrontation and defer the problem until it grows out of control. If this condition exists at your community, consider enacting a Collection Resolution that has teeth and hire either a professional management company or outside bookkeeping service. This is simply too important an issue to hope it will resolve itself. There is always more needs than money to fund them.