Think what we're talking about here: developing and building a router to compete with the glut of routers already produced, sold and in use by ISPs, Cisco, NetGear, ASUS, LinkSys, D-Link, Nest, Eero and Acer, among dozens of others (even Huawei, embedded in a billion locations). The reason they discontinued the AirPort back in the day was not because they were selling like iPhones. An Apple TV set? Same story. An Apple car? They'd be destroyed faster than DeLorean or Fisker!Why not the doodads? Their AppleTV, AirPods, and other doodads are great - best in class.
You cant grow if you dont expand categories. The ones that you list as “core” started out as a Doodad, like the Tablet because they saw phones and laptops get stale. The Watch is most definitely a doodad.
Demand can be driven by constantly improving your products and services. And spending R&D money finding out what your millions of customers really want. What they really really want!