Most people i know who mismanage their finances are likely those who have less money before, they are overwhelm by the success and forget that its just temporary, they are like one time millionaire, while its always the situation, those who can control impulse and have future plans, have higher chances to become more successful not because they know what will happen but have people around them who cares for them, but some also is also there to use them and left them when they have nothing, and turn out to be the rich.
I agree, as they think that the opportunity will stay they forgot to value the fortune that they've gained, and most of them thinks for luxuries before thinking of investment or business that may continue the flow, same deal with those players who comes out from nothing and when the chance to change their fortune they think it will never stop, but along the way contracts expired and nothing left for them but thos expense that they need to shoulder.