Hertz’s (HTZ) decision to let buyers complete the entire car purchasing process online comes at a moment when the auto market is shifting fast toward simple, digital buying habits. Over the past year, the company has added key partnerships, including a collaboration with Amazon (AMZN) Autos that pushed its e-commerce push into the headlines and put its inventory in front of a much larger audience. Industry forecasts suggest 15 percent of car purchases in the U.S. could be fully online by 2026, which makes ...