You may be mistaking cause and effect. Many poor people have grown up with such a dire outlook that instant gratification is all that's essentially worthwhile.
but it is only a result of their mistakes in younger age
This is just uncharitable Ayn Rand style sophistry. Environment and simple luck has a fantastically large multiplier on one's odds of being poor or not.
Luck is a factor but often I have met people (I grew up poor) whom don't play the odds in a rational way. For example a lottery ticket has a very low chance of paying off and yet many poor people play, those same people can't find the time or resources to submit a healthy number of resumes or job applications each week even though the odds of finding a better paying job (and one that can potentially lead to an even better paying job in a few years) is statistically speaking vastly more likely. My point being its luck to pick the correct number in a game of roulette but its up to you how many times you attempt to spin the wheel.
but it is only a result of their mistakes in younger age
This is just uncharitable Ayn Rand style sophistry. Environment and simple luck has a fantastically large multiplier on one's odds of being poor or not.