That’s ONE way to do it, and like you said it makes more sense for cars. But there are other approaches, like having a central ring that the outer surface of the tire will fall back on, or just filling the tire with foam.
I’m not sure what you’re riding, but many modern “sportbike” profile radial sport-touring tires are actually decent when they go flat. They use a heavy tread carcass and stiff but not run-flat stiff sidewalls. If you have a flat, it makes the bike definitely feel like something is wrong and it really only gets dangerous if you ignore the warning signs and the sidewalls fail. I’ve had flats numerous times in the past 10 years due to road debris or once a popped valve stem and while it wasn’t a walk in the park with sudden pressure loss, it wasn’t all that hard to get the bike to the freeway shoulder safely from 75mph+. A far cry from cruiser profile or those old bias things we rolled around on in the 80s.