I assume RAM will also be a major constraint for on device ML; most Macs still default to 8GB (with absurd bumps in price to upgrade) so I'd guess some very high percentage of Macs sold in last 2 years are going to be quite bad for any major new software stuff Apple release in 2024. That is assuming they even are supported at all; if Apple follow their iPhone playbook they might just release the new stuff on late 2024 Macs.
Releasing the (more) mainstream model “as early as the end of 2025” or about two and a half years from now seems pretty depressing if accurate.
Allowing another year for some kind of volume of sales that might justify the development of apps etc suggests we are a long way off this being a supported, mainstream computing platform.
Much harder to model but I’d assume quite important to consider.