Is doesn't seem like a smart move to take an unsecured bet with someone that you don't believe will pay. If you lost you would have to pay or be labeled a scammer. He has everything to win and nothing to lose. The most you can hope to do is not lose.
I understand what you are saying but in principle for me:
1. If I make a bet with someone I honour it... not because they need the money but because I keep my word or lose my reputation. An escrow is fine but doesn't change this.
2. Bitcoin was not going so low in so short a time. No question. That's why I took the bet. That's why 8 or so others jumped in also! And if China had announced banning Bitcoin an hour after the bet then bad luck for me.
Contrary to what you say TheCoinBull will lose his reputation if he doesn't pay. That's his choice to make. I'll leave that up to him.