I'm your age (plus or minus a year), and I know what you mean, but I think these days I would be sadder with the wrong girlfriend than no girlfriend if I really thought about it.
Ah, hell. Even that isn't really true. So these women are crazy; it is always nice to have someone around. How many people really want to be single? Although some of these women may be "okay" being single, I'll bet they aren't really happy. I don't know how many women around here in their mid-30s that I run into that suddenly realized they don't want to be single and become ultra-desperate as a result. They lied to themselves for so long that they swing to the opposite extreme psychologically, when the overwhelming weight of reality hits them.
At least you know exactly what you really want and are honest about it, trend du jour be damned. Emotional and psychological maturity goes a long way toward eventually finding a really rewarding relationship. A lot of the Super-Single-to-Suddenly-Desperate women find themselves in bad relationships due to rather excessive compromises. A disaster anyway you slice it.
As to why I meet so many of these women: I live in the greater San Francisco Bay Area. Enough said.
Really, I always thought that area the male-female ratio is way in the female's favor because you got (or had) a lot of tech jobs which tend to be filled overwhelmingly by males and being California which if I remember correctly is one of only 3 states that have more males than females (Alaska and Nevada are the others)
Granted it's San Fran and all those men for lack of better words "Aren't available", But I would still think most woman would have enough choices that they wouldn't get that desperate