Back then, low paid manual workers were little more than slaves. The unions served an important role against Lord-of-the-manor style company owners.
But they over-played their hand and the old mass employment industries have closed. We no longer have factories where children risk losing limbs while cleaning under working machinery. Which begs the question what do the mass unions actually offer today other than being fund raisers for leftist politics.
now with no unions people are slaves again with zero hour contracts and the threat of not being given any hours if you have to take a day off sick or to look after a sick child. large employers have way too many people than they need on the payroll on zero hours so there is always someone left suffering. its a cruel evil way of getting around employment laws that were set up to protect workers.