Wonderful essay, but when you write, "There's no Evolution Fairy who can watch the gene pool and say, "Hm, that gene seems to be spreading rapidly - I should distribute it to everyone", aren't you leaving out the classic evolution fairy, Cupid?

What Eliezer is saying here is that biological adaptations cannot get fixed in a population by "becoming common knowledge" and being universally adopted, the way innovations in the business and engineering world spread. Even an artificial breeding program has to work within these constraints: there's a limit to how much reproductive skew you can supply.