Picture this: It’s 2021. A SaaS founder stands in a Sand Hill Road boardroom, clicks to a slide showing 40% month-over-month revenue growth, and waits for the high-fives. The only question from the partners is, "How fast can you deploy our capital to hire more sales reps?" Now, fast-forward to 2026. That same founder is pitching a new fund. They show 12% MoM growth, but before they can finish the slide, a partner interrupts: "What is your gross-margin-adjusted CAC payback by channel? And how...