For the answer to the entitled proposition, I'll turn to the master of economic theory, Terry Pratchett, and one of his characters, Samuel Vimes, in what is termed "Sam Vimes Theory of Economic Injustice". Which reads as thus:
Simply put, it is more expensive to be poor than it is rich.
With the way good are manufactured, cheap goods are not designed to last, and need replacing far more often than expensive goods, which leads to an inherent inequality in the expenses of the poor as compared to those of the middle class, which is why it is far easier to become rich when starting from the middle class, than it is to become middle class, starting from being poor.
This, of course, is merely one factor, but it certainly does play a role.
Samuel Vimes earned thirty-eight dollars a month as a Captain of the Watch, plus allowances. A really good pair of leather boots, the sort that would last years and years, cost fifty dollars. This was beyond his pocket and the most he could hope for was an affordable pair of boots costing ten dollars, which might with luck last a year or so before he would need to resort to makeshift cardboard insoles so as to prolong the moment of shelling out another ten dollars.
Therefore over a period of ten years, he might have paid out a hundred dollars on boots, twice as much as the man who could afford fifty dollars up front ten years before. And he would still have wet feet.
Simply put, it is more expensive to be poor than it is rich.
With the way good are manufactured, cheap goods are not designed to last, and need replacing far more often than expensive goods, which leads to an inherent inequality in the expenses of the poor as compared to those of the middle class, which is why it is far easier to become rich when starting from the middle class, than it is to become middle class, starting from being poor.
This, of course, is merely one factor, but it certainly does play a role.