. . . this may be true but isn't natural selection still in effect?

@thundergod As in survival of the fittest microbes? Sure, but again, surface sanitizers are far more effective at completely killing them, regardless of class. The resistance comes from improper or over use of antibiotic medicines or, to a much lesser degree, our natural immune defenses that don't completely kill the organism, and allow the surviving remnants to mutate into one that is resistant to the usual defenses. The vast majority of that action occurs within the body. Viruses, themselves, are known for rapid mutation, though thankfully this one has not yet seemed to mutate into one that is more virulent. Lots of hypotheticals are possible, but nothing about this one shows that it is probable.