If the guy getting money for the toy, paid the people actually making the toy what they're worth, there wouldn't be billionaires. Your premise is flawed because you assume billionaires are good people who worked for their gains, when in reality every single billionaire in excistance has abused their workers, at minimum, by not paying them their actual worth.
Add to that the psychotic greed. When they reached say 500 million, why keep hording more money? They could lower the price of the product to the point of being a non profit, or paying their employees instead of themselves. They would never need more money in their life, but no, they'd rather hoard money, than let their employees live as comfortably as themselves.
There are no ethical billionaires.