It is a fundamental feature of capitalism. There is an inherent tension between employers and workers, in that workers represent a cost center that can never be totally eliminated, and has a lot of undesirable features, such as: being alive, having opinions, being able to talk/whistle-blow, requiring bathrooms, bathroom breaks, and safe working conditions, banding together to increase their collective power and reduce exploitation, and worst of all, necessary; you can't ever get rid of them all!

The history of capitalism is the history of grappling with this inherent tension, and companies finding novel ways to deal with it. Gig work, union-busting, "right-to-work", non-competes, NDAs, return to office, employee tracking software, automation, robotics, AI, etc. The most effective trick though, was convincing the workers that they definitely don't ever need to band together, and you as an individual are definitely better off negotiating alone versus entire corporations.