Luck? of an Irishman

What baffles me about this case and similar cases where people have amassed millions of dollars through both legal or illegal means yet continue striving to increase that wealth by the continued breaking of the law, or breaking it the first time, in order to amass more money, which deeds often lands these people in jail. I mean, if most people possessed $60 million, I think they would find that sufficient for living out their remaining days in comfort. Greedy hubris before the fall, I guess, or maybe the compulsion to gamble may be the primum mobile of the people in question.