Now if I replace them all with robots, aside from the upfront and maintenance costs, I don't pay anybody anything. Now, a lot of people are going to say that the owner deserves to pocket the difference because he was innovative or reduced costs or whatever. But either way, notice the factory still makes the same amount of money. It just doesn't have to pay workers anymore.
So now we have a political debate, and you get all these people saying that those workers should just find a new job, and if they don't have the skills they're just lazy, don't deserve handouts, etc. I think it's sad that people think this way, but I'm not going to try to argue it because it's pointless. But if this side wins out, you'll find in the future that our country looks very 3rd world. A large wealth divide, lots of crime, little opportunity for advancement if you're not already wealthy.
So how do you stop that from happening? Well, the factory owner probably deserves something for being innovative, sure. But the people that lost their jobs do too. If we get to the point where the population is a lot larger than the job pool, you basically get to pick basic income or 3rd world. There's really no other option.
You can deny this all you want now - go ahead. If you want to do this, I'm not going to pretend I can convince you otherwise.
One more thing though - people have jobs today not because they inherently need them, it's because some entrepreneur needs to hire people to get things done. No business person wants to spend money to hire someone they don't have to, so if we get to the point where most jobs can be automated, then we have a mostly unemployed society. We can decide how we want to handle that, but we can't really stop it from happening.