> yes, if a chip doesn't make M4 Max, it can make M4 Pro. If not, M4. If not, A18 Pro. If not that, A18.

No, that's entirely wrong. All of those are different dies. The larger chips wouldn't even fit in phones, or most iPad motherboards, and I'm not sure a M4 Max or M4 Pro SoC package could even fit in a MacBook Air.

As a general rule, if you think a company might ever be selling a piece of silicon with more than half of it disabled, you're probably wrong and need to re-check your facts and assumptions.