At least with Panfrost it made more sense bc it still being used
M1 chip laptops can only be bought second hand at this point
New M1 Macbook Airs are still available at Walmart (maybe elsewhere). But even if not, who cares? People are still writing code for computers that haven't been sold since the 1980s.
As the other replies show, you can still buy this machine, but it sounds like it likely won't be for too much longer
The developers involved must be acutely aware of it. Maybe they have some sense that the work will easily update to current M chips. Or maybe they don't really care about that. It was just an interesting exercise and they move on