Re: More likely is the end of macOS
Apple computers are disproportionately prominent in a few markets: publishing, video, photography, education.
Too many of the core Mac use cases would vanish if it became a glorified iPad, and thankfully with sales of the latter now well down from their peak, it has lost its waymarker sheen. Similarly, the Mac App Store is largely moribund.
I therefore strongly doubt that Apple would kill macOS, whether explicitly or only in effect.