Also, if you are looking for a partner approximately in your age, the best ones are already taken. (Maybe this shouldn't bother you, because if you are still single, the best ones were probably out of your league anyway.)

I don't find this to be particularly true. I don't even know if the converse ("the worst ones are least likely to be taken") is true.

My definition of "the best ones" tends to include people who have invested a lot of energy into themselves and their careers, and thus made themselves less available and appealing on the dating market during their college years and mid-twenties.

In fact, when I casually look over my Facebook friend's list, "the best ones" tend to remain single even after thirty, because they're doing their physician's residency, or undertaking a scientific expedition in a remote jungle, or something along those lines.

If "best ones" means "hottest ones", well, people become suddenly single later in life for a wide variety of reasons.