If you stayed on the land you had to work, not quite like a slave, but close. And if you disagreed with this, the government had an army that convinced you ...
Factories offered a better alternative than that, and yes, mostly because the agricultural option was just not open, and just not worth it. They also offered a great density of people that made the labor movement possible in the first place.
Most of the writing comparing factory work to agricultural work is from after the enclosure movement forced large portions of the agricultural working class to take the "wage work" arrangement with a similarly brutal schedule and work pace to factory work. You're right that the technological and agricultural advances that led to enclosure created a source of poor workers willing to accept factory work.
Obviously the peasants weren't spending the rest of the time sitting around, they had to work on their own land to keep themselves fed and clothed. It definitely wasn't some sort of lazy paradise, subsistence farming is a brutal and unstable way of life, I'm just arguing that the early Industrial period was even worse. If you want an "objective" measure of quality of life across vastly different time periods, the height of the average European went down a few inches during the Industrial Revolution due to malnutrition and overwork, and only recovered to its preindustrial average in the first half of the 20th century.
Now with the tech era, you can snoop into people businesses and control in a "softer" way. With AI, you might be able to bypass the knowledge workers who enjoyed a pleasurably life in the last 30 years or so. This is mostly because knowledge workers will sabotage your operation if not treated well.
Now this might not longer be the case as you'd no longer need them. The revolution can't happen if the people have no leverage: 1. either be able to defend against a professional army or 2. are an input in your supply chain and can stop your operations.