> All of Apple's M chips so far have been primarily designed for mobile use

There, you said it again. This is wrong - you hear Apple M chip and you think "laptop" primarily, but that is no longer true. Just as it would be to say ARM is primarily for smartphones. Now I don't want to talk about sales numbers, but the M chips in the Apple Studio and Mac Pro (and those used by other manufacturers in servers) are a different category than "laptop". For a quick shallow impression see: https://nanoreview.net/en/cpu-compare/intel-core-i9-14900k-v...

(nevermind it's the i9-14900K)

Again, the I9 is more powerful, but that doesn't make all of ARM or M a "laptop".