How Founders Mistake Traction for Product-Market Fit and Scale Too Soon

What if the biggest bottleneck to scaling your startup isn't market demand; it's internal alignment? In this episode of Built Not Born, host Sage Nye sits down with Carter Cast, former CEO of Walmart.com and Professor of Entrepreneurship at Northwestern University, to unpack a hard truth: most startups don’t fail from lack of demand, they fail from lack of alignment. Carter explains why mission clarity must precede growth and how misalignment at the top quietly fractures teams as companies scale. He breaks down what real product-market fit looks like (hint: it’s not fueled by discounts), and why sustainable unit economics are the only green light to accelerate. The conversation also dives into leadership, what separates high-performing teams from dysfunctional ones, how to navigate the shift from generalists to specialists, and why motivation mismatch often masquerades as underperformance. Above all, Carter makes a compelling case that self-awareness isn’t a soft skill; it’s the ultimate competitive advantage that defines how far a founder can go.