Re-post. 'Boots' theory of socio-economic unfairness

Re-post
When he was a little boy, Sam Vimes had thought that the very rich ate off gold plates and lived in marble houses.
He' learned something new: the very very rich could afford to be poor. <...> The reason that the rich were so rich, Vimes reasoned, was because they managed to send less money.
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.<...>
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.

Men at Arms by Terry Pratchett