And what is alpha is always relative to something else, which means that rising female incomes, for instance, will raise the bar for competition.
http://en.wikipedia.org/wiki/Hypergamy
http://heartiste.wordpress.com/2012/02/09/female-hypergamy-g...
http://hawaiianlibertarian.blogspot.com/2009/10/its-all-abou...
Supposedly, only something like 40% of men got to reproduce in the Neolithic...
A richer hubby presumably increases survival chances for the offspring (independent of the actual biological father of said offspring). But the fact remains that a woman can easily get laid any time, if she wants to.
There was this famous experiment where students approached other students on university campus and asked them if they would like to have sex. Don't recall the numbers, but there was a real high discrepancy between the sexes, basically most men who were approached by women said yes, whereas hardly any women said yes. So basically as a chick, just walk up to some men and ask.
Of course modern society complicates it a bit because men now have the risk of paternity charges (a societal construct).
The googling brought up lots of fun stuff :-)
1) Only done on 16 girls. Sample size is small. 2) More than 30 years old. Changing mores. 3) Women are likely to fear random men who approach them, the reverse is not true. This experiment should have been done differently: they should have achieved some rapport/comfort with the mark and created some sexual tension, and then asked for sex. My guess is that at least a few of the women would have responded favorably in that case.
Therefore women are "the price" and men have to compete to get them (and by compete I mean "scramble and write hundreds of messages"). Women don't really have to compete to get pregnant.