So you can't sue him because you won't get any money, but he can't scam you because then you'll sue him? You're sort of proving my point. If he stops talking to you, you'll sue him, but you don't think suing him will get anywhere, so why should he do anything when he can just talk to you once a week and keep you happy?
My talking! I really think many of those people that got scammed don't actually do anything to get their money back. It may be because a lot of jursidictions still don't actually pursue legal actions against bitcoin thefts. Also many just don't expect to succeed and just give in - especially when there are a lot of people that got scammed for relatively small amounts each.