it's a very simple arithmetic. In a society that normalized promiscuity to an extent several women can now date a single guy. They don't even need a "hoe phase" or do one night stands for this to happen. One is hooking up with him only for sex, the other hopes of something more, the third is ok with a temporary "situationship". This means 3 women for 1 guy. Which means several guys are left without date, while others have a "rooster". They can sift through literally hundreds of options. And they don't even have to settle for one. Our atomized, permissive society allows for an indefinite period of "dating around". So women today keep themselves available for years of fun and entertaining the hope of securing the hot guy. They aren't really "in a relationship", but they also aren't available for the average guys in the middle of the bell curve. He on the other hand stays single the whole time.