This is an excellent primer on the problem of beauty from a Darwinian perspective. Why Extravagant Beauty is Evolution’s Most Persistent Problem.
It seems more reasonable, as Wallace believed, that extravagant beauty is likely to eject creatures from the gene pool. It requires more energy to develop and maintain and makes one highly conspicuous and attractive to predators.
A quibble: I am not sure this is Darwinian evolution’s most persistent problem. There are so many candidates for that title, it is hard to keep count, much less come to a definitive answer as to which problem is the worst.