And what do you think would happen if unions were made illegal? Employers would just play nice? It's crazy how far propaganda has gone in the US, where the average worker is longing for a return to the Gildee Age.
No, it's in their interest to squeeze as much work from them for as little pay as possible, to maximize short-term profits. And that's how it was during the Gilded Age, before unions: workers were treated like a disposable and abundant resource.
