I don’t see the scenario where Apple starts with the iMac. The 2019 iMac was fine. It’s on the low-power side where Apple’s CPUs would be particularly interesting alternatives for a start.
So suppose we see ARM Macs in 2021; it’ll probably come to the iMac in 2022. That would mean three years of no upgrades. Nah. Instead, Comet Lake now, Rocket/Alder/Tiger Lake next, maybe then ARM.
A start. Exactly. I would never see Apple completely abandoning Intel in fell swoop. People can “ooo” and “ahh” all they want, and speculate until the cows come home, but there’s nothing to indicate that is going to happen any time soon, other than maybe an ARM-based MacBook to start. This has been rumored for so long, I can’t believe it hasn’t been relegated to vaporware.