It goes to the beginning. If a union did not present a threat of violence and sabotage towards any company that dared to hire replacement workers, than a strike would just be a mass resignation.
I read about the Ford strike back in the 30’s ... then the Pullman strike as well. Unions had their reasons back then but when management saw the writing on the wall they treated their employees better starting with Henry Ford. Now they’re just a management system themselves and all they have is threats not only to companies but to individual employees as well. I hate the term ‘workers’ since it’s so communistic sounding.