(Author here.) Very few people would outright say "I'm going to defect here, you'll do the work anyway". They might say "that sounds like a great idea, but I p

(Author here.) Very few people would outright say "I'm going to defect here, you'll do the work anyway". They might say "that sounds like a great idea, but I promised my kids we'd go to Disneyland this weekend". And next week, "I promised my wife some alone time". Then, "my herd is coming down with something, I need to pick up some antibiotics". And so on, until you give up and dig it yourself. And if you install a pump in a village and ask people to pay to use it without enforcing that, they might say "I'm not going to pay, water should be free". It would be naive to try to model everything as a simple one-shot game. It would also be naive to think that simple one-shot games don't usefully model real life at all. Just look at https://en.wikipedia.org/wiki/Prisoner%27s_dilemma#Real-life_examples https://en.wikipedia.org/wiki/Prisoner%27s_dilemma#Real-life... and see how many players defect. However, I agree that I should probably have included some discussion of iterated versions.