> ... Algorithms could be used to prevent firing an employee in such a situation.
I think you're being _very_ optimistic and a bit naive about the motivations of a business that would resort to such algorithms.
They want to maximize the throughput rate of picking boxes and minimize their cost. Sure, it sounds "objective" to say that everyone who doesn't meet the pre-agreed work criteria would be fired (and not-fired if they meet it).
But who gets to set that threshold? Who determines what is reasonable? What if that performance threshold can only be met by fit young people and only until their bodies can't take the stress anymore? How will workers even assess whether or not they can do the job until they try?
This is an ugly practice. If it survives, it will be coming to a cubicle near you someday. Hope I am retired by then.