A recent article broke out on vice of women complaining there aren't enough single men for them to date/marry in the US despite there being over more than 1 million men than women in the US.
The reason there aren't enough men comes from women's ability to not compromise on what they want in a man until they get REALLY DESPERATE (i.e. I want to start a family).
Analysis of women in the US:
1. HYPERGAMY (Found in the female gender)
Hypergamy: if you make $34k, you're in the top 1% of the world in terms of wealth. $34k is a lower-than-average salary in the USA. Since the USA is a fairly wealthy country, women in the US can't go to many other countries to "date up", whereas men from the US can "date down" all over the world. This makes US women very selective compared to other women around the world - if they have an average US job, only 1% of men in the world will be eligible to date them.
Over 65% of US women are overweight or obese. This will tend to make the men compete for the less than 35% that have normal figures, and thus the attractive women are that much more selective. (Over 70% of US men are overweight or obese, and they will still be competing to date slim women.) Other countries obviously don't have this sort of obesity problem, so there are more attractive women to go around, and being slender and attractive isn't so rare even as women age.
Average height of US woman is not the tallest but fairly tall (5 ft 5) compared to women in the rest of the world due to good nutrition (maybe too good). Women generally want to date men who are taller. Ideally a man is perfect for a woman if he has a height that is 6'2. Only 5% of males are taller than 6'2. Being 6'2 places you in top 95th percentile in terms of height.
The US has a half million more men than women 20-39 years of age. Given that most people pair up, this is going to magnify the ratio of single men to women. It is especially tough in the Western US where the male/female ratio is the highest.
5. Racial preferences
While many populations have racial preferences, OK Cupid data shows that white American women like sticking to white men, and Latin- and Asian-American women favor white men even more.
The rest of the world tends to be more accepting of other races on average. I've heard figures that 20% of the world is white, but even if it is more than this, US women will still overwhelmingly filter out men from other parts of the world.
Feminism: magnifies all of the above due to making hypergamy more openly acceptable, fat feminism/fat acceptance, and encouraging women to work which makes dating up even harder.
7. White Knighting
Thanks to certain men taking it upon themselves to believe that telling women they are beautiful every single day, and awesome. While demonzing their own gender as worthless and misognistic. would somehow bring them closer to getting laid/having a girlfrined. Many women have an unrealistic expectation of their own worth/beauty and what kind of guy they deserve. Thinking that without/little effort on their part that they deserve a tall, handsome, successful male just because they were born with a vagina and happen to have a BMI of 25 or less.
Seeing many men who are near the top in looks are willing to throw an ugly/average girl a chance at sleeping with them, many women confuse this as them having a chance at getting these guys for relationship. What they don't seem to understand is rich and/or handsome men have no business in committing to you and the only thing they were after was your vagina. This doesn't hit a lot of women until they are well into their 30's now being reasonable in their expectations on mates and want someone to settle down with them.