> That's not strictly true, performance of a transistor still has value. Companies like Apple pay premiums to get in early on leading edge nodes, more per device than the mature nodes they move from.
Apple can't increase the price of their product arbitrarily. So if the price per performance increases, the new iPhone would be slower than the old one. Maybe people will still buy it if it has better power efficiency, but that is a trade-off which has its limits.