- Polygyny (more male serial daters than female. i.e. "CADS" and "Chads"). Only good looking men are very sexually active, where as females don't need to be good looking to get a regular free supply of sex. Most women just need to not be fat. Even then there's a large market for BBW/obese/disabled females and other niches.
- Looks Hypergamy. More average-looking females are looking to date up in looks than average-looking males looking to date up, esp for short flings; just look how Tinder and most dating sites works like this, and even promote this behaviour. Call it the 80/20 rule or what not. Whilst an average-looking man struggles to get women in his own league (average women), the average women themselves will be presented with opportunities to not only shun hundreds of guys in their own league, but they are very able to get handsome men above themselves. This has only become magnified greatly in the digital age, where an average woman (as long as she's not too fat) can call up a hot stud online like ordering Pizza.
- Stronger competition from older men for younger women (16-34 ish). Your average slim or attractive 25yo female is getting hit on by much older men, younger men etc.
- High Obesity rates of women (and men) in the west, meaning more men would rather be alone than be with obese females.
- Just natural order that more males miss out on reproductive opportunities than females.
- Prolonged Appearance-based rejection is more damaging for males (I've studied this in great depth). Lots of guys simply accept they're unattractive and give up actively looking.
- The "Lek Paradox" - its where females look for males with distinct ornamentation, and very few men have all these correct traits of ornamentation (height, chiselled masculine handsome face, muscles, great hair, dense stubble). See "Sexy Son Hypothesis". https://en.wikipedia.org/wiki/Sexy_son_hypothesis