Previously you said this assertion of Mayr's was "literally true":
"All the individuals of a population... are exposed to the adversity of the environment, and almost all of them perish or fail to reproduce." (E. Mayr, 2001)Now you are saying it is literally false.
No I'm not. Change in populations is a result of differential reproductive success. Even in humans a large percentage -- a third or more -- of conceptions do not come to term. And that is after conception. Variation takes place prior to conception, and most variants of sperm and egg fail. It is selection after variation that weeds out bad mutations, and in sexually reproducing organisms, there are hundreds of eggs and millions of sperm cells produced for every pair that result in a reproducing adult.