Not all competition is mediated via markets. Mushrooms will compete by injecting themselves into their adversaries using their own internal pressure.
Yeha, but they are showing an instance of nature in which things work one way and ask "why can’t humans XYZ if even a mushroom can? ", but there are also plenty of instances in which nature is savage.
There is a constant war in the roots of trees, does that mean humans should be in constant war?
Plus, there IS a profit incentive. Those mushrooms are trading. What they get in return is the profit incentive.
Trading for food to eat is now “profit incentive”? How is there profit if you consume what you take?
Edit: and don’t get me started on the violence used in our own market systems. Thankfully Mushrooms learned long ago to eat the rich, because “surplus profit” are just resources that aren’t being used.