he outplayed maldy and took everything he ever owned except for his daughter, who now despises old gally lol
goblin society works in a pretty simple way: if he's paying, you're serving. it's all pretty much corporatist. your social standing depends on how many people you can buy. if you can buy everybody, you are the boss.
trade princes are not elected. the position isn't hereditary either. they have do to whatever it takes and use all the resources they have to get all the power and reach the top. considering goblin society is 100% based on commerce and gold, and that the leader is called the "trade" prince, what do you think is the ultimate expression of goblin power? that's right: money!
it's not stated directly anywhere that the trade prince is the richest guy, but the trade prince is the most powerful guy who killed and schemed his way to the top. considering goblin power = money, than the trade prince IS the richest guy.
though sometimes I wish the new trade prince were gallywix's dad. he'd lose his position within the week, but it would have been funny