It's not "just happen to use the same Arm instruction set," it's "they keep up to date with advances in the Arm architecture, such as v8.x extensions, which are heavily influenced by what Arm plans in their roadmaps."

If instructions/extensions are being made that improve laptop-class performance in some ways, then that likely does increase the chance of Apple making laptop-class Arm cores for their Macs, even if by a miniscule amount.