but / on the other hand的区别

but / on the other hand的区别
He kept wondering why people who had so much money were never satisfied but were always wanting more.
这里的but 如果用on the other hand
即:He kept wondering why people who had so much money were never satisfied ,on the other hand,they were always wanting more.(还是要用on the contrary?)
或者用 whereas
既::He kept wondering why people who had so much money were never satisfied whereas they were always wanting more.