The trajectory is obvious, and includes iPhone. You don't need three different chips, just different interfaces. One unified computing and storage general purpose computer, available via mobile, audio (Airpods), visual (AR), large UI (Macbook / Mac), health (Watch), etc. They're already unifying under M1 / ARM.
It's far from obvious to me. Unifying back ends and unifying products are night and day propositions. Nothing Apple is doing points towards a thin-client strategy.
