Sure, sexual selection exists, but in nature, the traits that are typically sexually selected for are proxies for health, freedom from parasites, vigor, access to food, etc… Generally speaking, the creatures with those attributes are going to have more successful offspring, etc… because of what the traits signify.
For example, all male peacocks have the genetic makeup to have the big tails. Some may have genes predisposing them to bigger or brighter tails, but ultimately the thing that makes the difference in tail size is that the ones with the biggest tails are stronger, faster, smarter, or just lucky enough to have adequate food. So they mate and their offspring are hopefully stronger, faster, smarter or luckier as well, and grow big tails, and are more successful than the other smaller-tailed peacock’s offspring.
They’re not being selected for bigger tails genetically, but rather to be stronger, faster, smarter or luckier.
That’s the fallacy that you’re suggesting is happening in people- that we’re being selected as a population to be better looking, and that’s just not the case because the pretty/ugly indicators just don’t actually indicate anything now that we’re civilized- just about everyone has adequate access to food, and the offspring of ugly people aren’t disadvantaged in any evolutionary way that would cause them to be less numerous or successful than pretty people’s offspring.