Nah, it's easier than that. Putting two chefs in the same kitchen doesn't let you cook twice the amount of food in the same amount of time, because sometimes the two chefs need to use the same resource at the same time - e.g. sink, counter space, oven. But, the additional chef does improve the utilization of the kitchen equipment, leaving fewer things unused.

Maybe simplify more to make the concept of shared resource explicit.

2 chefs with one stove. As long as they're doing other things than frying it's ok and speeding things up but once they both need the stove you're down to 1 working and 1 waiting.