There’s a fabulous quote floating around from Scott Kirby, the CEO of United Airlines. When asked about the future of low-cost carriers, he said, “The low-cost model is dead. It was designed to screw the customer.” That’s a pretty bold statement. And it caught my attention—not just because it’s rare for a CEO to speak that candidly—but because it’s true in a much broader sense than airlines. If you’ve ever tried to run a “low-cost” version of your business—cheaper aligners, faster appointments, tighter schedules, less training—you know exactly what he means. JetBlue is a good case study. They started out…