I don't know you came about checking the ratio of your supposed stats but I do also feel some how when their is an increase in the bank roll of the gambler the risk involved is alot lesser per say the number of game accumulated will be reduced and the risk also will not be too much.
Poor people mostly lose because poor people are afraid to take the second risk and they don't have money to take a second risk or invest. There can be many other reasons such as those who are a little poorer mostly withdraw funds or withdraw portions of the profit and those who are rich keep the portion of the profit. As a result, the success rate of the rich is much higher than that of the poor.