Sexual selection differs from most forms of natural selection in ways tailor-made for pushing traits to their extreme. For one thing, sexual selection can be a lot stronger than natural selection. Whenever a small subset of males monopolizes access to large numbers of females, the disparity in reproductive success skyrockets. A few victorious males sire dozens or even hundreds of offspring, while the overwhelming majority of males sire none. When payoffs for success are high enough, weapons can evolve to really big sizes.

Emlen, Douglas J, Animal Weapons_ The Evoluti…, loc. 177