Just so we are clear, there is multiple areas of efficiency
Let's see if this is your definition
A group of 10 workers makes widgets. Under a capitalist system they make 50 widgets, so 5 widgets per person. Under a worker run system they make 60 because of morale so they are more efficient. I agree this can happen, and the workers can be more efficient in this scenario.
However the other scenarios
10 workers around, 50 widgets are needed. How do the workers get organized to make the 50 or 60 widgets? How quickly can that happen?
10 workers, but now 100 widgets are needed.
10 workers working, but only 50 widgets needed
10 workers working, but now it's 50 lemons needed
10 workers working, but no widgets are needed
The efficiency of the worker owned system is only in the first case, not the other cases.
but prove me wrong. You three find a large room, find at least 47 other people and meet and in that meeting have all 50 people agree on a new business that provides a service or product and how your company will be run. It should be easy since getting 50 together and then 50 to agree on it, should be ok.