It's a rhetorical question. I don't believe that there are anything like the numbers you say that are not working but are able, willing and reliable. This is on the basis of practical experience of a great many factories. If you're right and I'm wrong, where are these people? As to what you might want, that's largely irrelevant. I am damn sure that I don't want to be in a chicken factory, who in their right mind would? They are horrible places. However I've just done a 6 month stint in one, I'm having a week off and next week I'll be in a bigger one, bigger role, high pressure, just as unpleasant and exhausting. That's why they call it work, it's why they pay you for your trouble. However we all want to eat, the animals don't die of their own accord, and I can't see you rearing your own and doing your own slaughter, evisceration and butchery, so someone needs to be employed to do the necessarily unpleasant work.I don't know and I don't know what makes you think I would? Probably because they don't want to. I do know I personally would never work in a food factory unless maintenance of the Buildings or grounds and even then I think the smell would put me off.
As for who does it, we all have to acknowledge the need to contribute to society. Nobody deserves a free ride. Children do while they are in education, the elderly have done their time, the sick, injured, inform or incapable need to be cared for. But the vast majority of us need to pay our way, if for no other reason than to be able to care for the sick, old, etc. Nobody wants to clean out sewers, but someone has to.