Not matter what pads / rotors you put on 15 year old brakes fluid is 15 year old brake fluid. If you fully flushed the system with new brake fluid I’m confident you would not have experianced fade street driving.
Did you know its recommended to change the stock (DOT 3) brake fluid ANNUALLY! I don’t know many people who do that, and the ones I know who do never experiance brake fad on the street with a stock setup. The most overlooked part of brake upgrades is the fluid.
Coles notes* Change your fluids annually or semi annually its not water and it will lose some properties after a while.