Last week saw some major movement in the third-party delivery world. First, the New York Times pointed out how much delivery truly costs the consumer, noting in a headline that delivery charges can often nearly double the cost of the order itself. Then DoorDash, the industry leader with at least a third of the delivery market, announced that it plans to IPO. DoorDash last raised money at a staggering $13 billion valuation, which is equivalent to the market cap of Domino’s Pizza, the seventh....