From the article:
In an FAQ on the union’s website, it’s explained that discussions of a union began after the layoffs at CD Projekt, which amounted to roughly 100 people. “This event created a tremendous amount of stress and insecurity, affecting our mental health and leading to the creation of this union in response,” reads the FAQ. "Having a union means having more security, transparency, better protection, and a stronger voice in times of crisis.
Devs are not as easy to replace as factory workers, EU and US/CA software talent is top tier. I’d imagine even factory workers aren’t so easy to replace these days.