"There's no point surviving if you do not procreate"
Well, depends what you view as worthwhile.
Take the works of Leonardo da Vinci, Einstein, Shakespeare, Dickens, Mozart, Beethoven.
If they had never procreated, was there a purpose to them having lived? Absolutely there is.
Human knowledge or talent allows us to pass on information that enhances quality of life, improves quality of life, even without our own genetic input.
Incidentally, many of those on that list had a disability, too.
So...if a person's life means that we learn something or helps us appreciate the world around us, that IS a contribution to society that helps our overall 'fitness'. Those qualities are not limited to genius.
Jean Vanier talks about the work he does with those with a learning disability. Well worth seeing his videos online/getting his books. He sees that kind of 'added value' in each person, and explains it far better than I can.