This is a good place to post this:

en.wikipedia.org/wiki/Boots_theory

The reason that the rich were so rich, Vimes reasoned, was because they managed to spend less money. Take boots, for example. … 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. … 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 a 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.

Fast fashion wants you to have clothes that don’t last and that you buy and throw away on a whim. Someone who has the same clothes that don’t wear out in ten years doesn’t make the company nearly as much money.