Here's a counter-argument, union-focused:
What if you make 10 widgets and I make 5 widgets, but the next step in the assembly line is to insert those widgets into a larger machine and that process is timed to perform at 5 widgets per hour? What happens to the extra 5 widgets that you made? What are the costs of removing those widgets from the assembly line and storing them?
Can one over-produce in a way that degrades value once the sweet-spot of supply and demand is passed?
-PJ
What you describe sounds like the old Soviet method of manufacturing, in which the goal was not to produce anything of quality, or even functional items. The goal was to produce a quota.
So, for example, a washing machine factory might have a quota to produce 200 washing machines per month. Maybe they had parts for only 100 machines. They would make those 100, and then go on to make another 100 that simply did not have whatever parts were missing. So they might not have agitator shafts, or motor belts, or tubs, or whatever. But that didn’t matter—as long as the factory met its quota.
And I’m sure all the workers were paid exactly the same.
That’s the problem with divorcing productivity from wages and using measures of productivity that are equally divorced from real-world considerations. Unions and leftists want to view the employer as a vehicle for keeping workers employed, regardless of outcome, and the outcome in those situations shows it.