There are some people who actually spend the entire amount of money in their hands on their household and other unnecessary activities. They waste money on things they don't need and run out of money. Which in one word is called wastage. All these people do not know how to use their money. They don't think about the future. And they continue to waste their money. And because of these reasons some people remain poor.
One of the reasons is indeed as if conveyed in your writing. namely being extravagant or not being good at saving or in another sense is because you can't manage your finances properly. But another thing that makes it difficult for poor people to leave poverty is because they find it difficult to build relationships, they are belittled and sometimes their skills are not really appreciated. and yes there are many other reasons that have been discussed in this thread at length.