Take the laxative and start thinking. Machiavelli described Renaissance political life of his times - which was THE survival of the fittest [rulers on that occasion]. The same thing happened in the earlier centuries, too [take his "history of Florence", for example] - but the description to be gleaned from "the Prince" is the most direct hence the best. And if Machiavelli's instructions are not Darwinistic, then what are they? Again, start thinking [after the laxative works].
"Rulers" make a very small faction of the population/society, even if very visible.
And if Machiavelli's instructions are not Darwinistic, then what are they? Again, start thinking
Even if Machiavelli recommended that the members of the society as a whole live according to the Darwinian competition (very dubious claim) it would not follow that the actual society listened to his advice.