> But I do wonder how much of its workability hinges on Basque nationalism rechanneled into something more useful than nationalism usually is.
Basically none, it does not hinge on that.
If anything basque nationalism hurts the proyect more than it helps. Many of the workers in the basque country came "to disrupt" basque nationalism. So many of the old workforce in Mondragon is not basque born.
there was a civil war in spain, most of the industrial capacity was destroyed in the country but not in the basque country. There was a nationalist movement there, so the far right dictatorship thought they had a great strategy. Move people from poor spain to the basque country, you utilise the little industry that remains and you take over the nationalism with people who feel spanish.
The only bit of Basque "nationalism" that helped mondragon was that many of its competitors were kicked out. In the 70s and 80s a ton of american companies came to Spain, the far right dictator hiding his axis friends allied with america in exchange for some military bases and allowed american expansion in Spain. Basque country having some of the largest industrial network was a prime candidate for their location. Then the 80s and 90s had a ton of terrorism which scared american companies which left industrial giants like Mondragon without competition.
So basque nationalism played little part in its success, its more like the American boom of the 1950s, everyone else had a detroyed industry and they didnt so there was a boom. Basque country had the same thing but instead of building coca cola and taking over south american countries to sell cheap bananas they opened cooperatives. There is little reason other than chance that Sillicon Valley is not like that, early companies like IBM could have set up as coopearatives and their early advanatge would not have been disrupted in the sleightest.