You’re correct, but it’s important to note that the M chips are very expensive to produce, and abandoning x86 means literally all the software iOS and OSX uses needs to be rewritten (or translated via Rosetta). It’s a huge project with tons of risks and massive costs. Apple can do this because they’re pretty much completely vertically integrated at this point, and control their ecosystem completely. If amd independently released some new non compatible architecture that was dramatically faster, it’d likely be dead in the water.

Intel learned this lesson the hard way during the Itanic days. AMD took the relatively safer approach when they released amd64.