Why do you think Uber couldn't function without signing up poor drivers (veterans or otherwise)? Hard to judge anyone's economic circumstances from a 15 minute

Why do you think Uber couldn't function without signing up poor drivers (veterans or otherwise)? Hard to judge anyone's economic circumstances from a 15 minute ride, but anecdotally most of my drivers have seemed to be folks with available hours and an available car looking to make some extra money. Never heard anyone describe Uber as something they were forced into by circumstance.