Apple Silicon Macs are likely to be supported for years and years.. the fact they are still releasing new models with 8 GB base RAM means even the first M1 Macs with 8 GB should do fine for years and years to come. Apple have created themselves a huge number of customers on new hardware with 8 GB RAM... who will be expecting at least 4 or 5 years run with what they just bought.I'm not talking about entry level models, I am talking about deals like BH Photos 64 GB/4TB M1 Max 16 inch. That laptop is not gonna go obsolete anytime soon. That's a better bargain for many than the M3 if all they want is a bigger screen. By the time Apple starts phasing support, you probably could score a second hand M7 or M8.
Irrespective of what they are actually running on it, in terms of third party software.