There are only two requirements for an on-demand service economy to work, and neither is an iPhone. First, the market being addressed needs to be big enough to scale—food, laundry, taxi rides. Without that, it’s just a concierge service for the rich rather than a disruptive paradigm shift, as a venture capitalist might say. Second, and perhaps more importantly, there needs to be a large enough labor class willing to work at wages that customers consider affordable and that the middlemen consider worthwhile for their profit margins.

Leo Mirani, “The Secret to the Uber Economy Is Wealth Inequality”