This is what bothers me. I'd understand it more if it were maybe a 7 or 8 year cycle like it used to be. My guess is that they're trying to fast-track the transition to Apple Silicon and are phasing out the old Intel models, but some of these hardware restrictions are a bit arbitrary.
If I'm spending upwards of $1200 on a computer, I'm justifying that expense knowing that the computer will last many years. If that computer won't last me years, I'll save money and just buy a cheaper model.
An even bigger concern is that many of the folks buying (for example) a 2020 Macbook Air aren't actually buying it in 2020. We've got folks from 2022 buying these things, and they're effectively going to get about 3 years or so of major software updates if Apple continues the current trend. For a $1000 computer, that's not a very good lifespan for full software support.