Earlier quoted context omitted.
That's not relevant. Apple is one of the worlds most valuable company, and they're stagnating. They've been hitting home-runs with products before, and creating new markets. Watch, even if it ends up eating the whole current market, but not creating new one, is a failure by Apple standards. Unless Apple is going to branch out and become company like Samsung, that makes everything from watches, to nuclear power plants…
So exactly what category of electronics do you propose that Apple can enter that has a larger worldwide penetration than the smart phone market - there are 2.72 billion smart phone users worldwide ( https://www.bankmycell.com/blog/how-many-phones-are-in-the-w... )?
They can still be very successful company without that. But not necessarily as one of the world most valuable companies.