Most startups don't die because they ran out of money. That's the symptom on seventy percent of the death certificates, not the disease. In this episode we rank the real causes by how often they actually kill, counting down to the true number one. Broken unit economics (19%) is the weakest, survivable cause, almost every fast-growing company passes through it. Founder conflict (23%) gets named constantly but it's a downstream symptom, a moderatable risk. Bad timing (29%) can be forced with enough money, but it's brutal for a small startup, see our Better Place teardown. Premature scaling kills seventy-four percent of fast-growing startups that collapse. And the real killer, at 42% percent, is building something nobody needs, no product-market fit. We close on how to use AI to de-risk demand before you build, simulated interviews, market analysis from real user language, and vibe-coding an MVP to verify demand instead of inventing it.