Have you met any poor people? Once you're poor you only buy something that you can afford right now, it doesn't matter that spending more would save you more money in the long run.
Take boots, for example. He earned thirty-eight dollars a month plus allowances. A really good pair of leather boots cost fifty dollars. But an affordable pair of boots, which were sort of OK for a season or two and then leaked like hell when the cardboard gave out, cost about ten dollars. Those were the kind of boots Vimes always bought, and wore until the soles were so thin that he could tell where he was in Ankh-Morpork on a foggy night by the feel of the cobbles.
But the thing was that good boots lasted for years and years. A man who could afford fifty dollars had a pair of boots that'd still be keeping his feet dry in ten years' time, while the poor man who could only afford cheap boots would have spent a hundred dollars on boots in the same time and would still have wet feet.
This was the Captain Samuel Vimes 'Boots' theory of socioeconomic unfairness.”
― Terry Pratchett, Men at Arms
Most rich people can lay out the $50 for the good boots.
Most poor people don’t turn rich.
Most poor people can’t wait to save up $50 for the good boots; they need boots now.
This all points to the lesson that wealth and riches aren't the same thing. Rich people are rich because they have wealth, even poor people can amass riches, say by winning the lottery, but can't be called wealthy until they actually have wealth.
A person can become wealthy off the efforts of other people, but if we want wealth for all, then it's society itself that must hold the wealth. This was Karl Marx's conclusion, but all attempts to build a society capable of holding wealth for all failed.
So we're stuck with trickle-down, the idea that the surplus wealth of the wealthy is good enough for all.