Good news, he doesn't have to because money only travels along reverse trust chains. If you don't trust Elon but Alice trusts Elon and you trust Alice, then it's actually Alice who is paying you directly to shove your friend's hand in a blender. Maybe reconsider your friendship with her.

Why wouldn't it lead to a bid war bringing exchange ratios arbitrarily close to 1? You may take a 70% cut of any transaction does with you, but Alice figures out if she charges a 50% cut, she gets to keep 50% and you keep nothing of that same transaction. Then Bob figures he can undercut Alice by charging only 30%...