Firstly, you have to consider that Apple has said the transition to ARM will take about two years. So it’s going to have to release a few more Intel Macs next year too.

For the less than five years bet, if you’re referring to macOS updates, I can personally bet my entire wealth (which is a decent figure) that you’ll lose. There’s no way the Intel Macs released this year are going to lose macOS support for another six years (into 2026), at the very least. The latest macOS (Big Sur) that’s now in beta supports models that are seven years old (or even older than that).

If you’re referring to hardware support and repairs, there are standard ages for each model that Apple uses for that purpose to define what’s obsolete, vintage, etc. I’m sure these will follow the same cycle.