I'm going to point it out, just because it needs to be pointed out. The people who pay in and never get paid out win because they don't die a long, horrible, drawn out, painful death or perhaps just don't live a long and painfully wretched life.
Insurance is a lottery, one that you just don't want to win. It is the same concept though, many people pay a fraction of what they might take out, so that a few people get to take out little bits here and there and one or two get a huge payout.