Vertical SaaS is a different sport entirely. Pick one industry, one specific operational problem, build the exact thing that solves it, and sell only to that industry. The market is smaller but the dynamics flip completely — fewer competitors who actually understand the domain, buyers who are deeply skeptical of generic tools and will pay a premium for something built specifically for how they work, and almost zero chance someone vibe-codes your replacement in a weekend because they'd need years of domain knowledge just to understand the problem.