I think that the issue is that even though school is a societal good (and presumably most teachers are motivated at least somewhat by altruism) it is also how t

I think that the issue is that even though school is a societal good (and presumably most teachers are motivated at least somewhat by altruism) it is also how teachers make their living. So the same forces involved in a private sector strike are in play, just with management replaced by the government, school board, or citizens.