Thurston Howell's favorite color was green. Why? Because Green is the color of money. His excessive desire for money was an obsession that made him greedy. After all, money was what made him strong; the more he had, the stronger he was.
On the island, his strength was weak. His power with money didn't get him anywhere; his power with money didn't get him anything. The only thing he gained from the other Castaways was respect,but not because he had money, but because he was an old man.
Mr. Howell, who stranded with bags of money had nothing to spend it on. I guess money can't buy everything; especially a one way ticket home.