Sam Altman closed out Startup School 2026 with a real answer to the PhD question — not "get the credential," but a structural claim about why startups cluster and win when they do. His argument: tech velocity, falling costs, and shrinking cycle times converge periodically — '98 dot-com, the App Store wave, and now — and incumbents lose their advantage fastest in exactly those windows. He goes further: this next wave probably rewards tool fluency over tenure specifically, becaus...