Those benefits came later, and slowly, after a lot of struggle for worker/female/child rights. Initially you had kids working 10h a day in coal mines because of the industrial revolution, steam machines needed the coal to run. Many people lost their jobs. There was of course also many great benefits, like cheaper textile making clothing much more affordable. With time the work force adapted to the new conditions, found new jobs, factories opened, and slowly the benefits outweighed the horrors of the transition.