Does the Basque region produce more engineers than other areas? I'm guessing their issue is more tied to the demographics of the area they are in and less of the compensation side of things. It's far harder to commit to a coop where your contribution is valued thousands of miles away and you don't have the immediate stake in things (e.g. your bar, bakery, barber, etc)
However, if your issues are tied to local characteristics, then (in maybe an abstract way) you still have another fundamental obstacle to scalability, not related to compensation..
(FWIW i think an interesting related question is whether YC might be able to scale outside SF if they werent so into the slogan “do things that dont scale” — which i sometimes interpret as the viridical paradox “scale by not scaling”)
There’s then also something deeper about making the trade-off between growth(rate) and stability..
OTOH photographer coops are quite common, here is a famous one https://en.wikipedia.com/wiki/Magnum_Photos