I find this not to be true, and to state generalizations about SF/SV dating scene or lack thereof, is also far off from the truth.
Have you ever heard of Okcupid? I'm a tech guy, in the tech scene, working for a tech startup, and have found that if you want to find/date women, you need to be proactive about it (kind of like the old days). The city, and the surrounding bay area are full of available women, who do want to meet "you"... just need to look
If you're not social, then you wont meet anyone in this city, especially if you moved here for a job, and have little friends, or time to meet people, hence why dating sites like Okcupid are essential. If you grew up here, then it might be easier as you have a larger network of friends, acquaintances - that generally leads to more social events, etc..
Also - last time i checked, we have about an equal ratio of men to women (does not include sexual orientation)