Charles Darwin's theory of natural selection is essentially playing out with the coronavirus right now where by relying on vaccines to eliminate the virus, we are giving an evolutionary advantage to strains of the virus resistant to existing vaccines, where they become the dominant strains of the virus. This is also what is giving some bacterial pathogens resistance to antibiotics as natural selection is giving an advantage to bacterial strains that are resistant to antibiotics.
While it's fine to have theories that explore different theories, and there are other forces and factors at work, ultimately the theory is demonstrably correct, and viruses and bacteria reproduce so quickly with generations measured in minutes rather than years you can literally see it happen in front of you.