Anyway, I polled everyone I personally know who grew up poor (by the definition above) and zero of them thought that Vimes' boots theory made sense. Additionally, on the specific quotes above, people found them laughable, with comments like
"what kind of poor person is buying a new shirt?" [the implication, too obvious to be stated, is that you'd get hand-me-downs or buying shirts at a secondhand store], "how much does this guy think it costs to operate a beater car?", and