Men may not physiologically, but psychologically toxic than any
Man gone to space, discovered vehicles, computer, build 100 plus storied building, cloned sheep, making artificial brain. Man also eradicated small pox, eradicating polio, made new plant varieties, new microbes, Genetic engineering, controlling HIV, TB etc to a particular limit. So I strongly doubt that will microbes be able to concur the world? I hope no. Men are potent or more toxic than microbes. It’s not just the potency of physiology but the potency of psychology.
I would like to justify that if a group of microbes succeed in making disease or fail the immune system of the body then they are physiologically more potent than the human. And if the immune system succeeds over the microbes then man is more potent than the microbes.
Consider the psychology, thinking, ideas to tackle the problem; as far as we know, men are bad guys than any thing else. so I hypothesis that the final world shall be of men not the microbes.