If a girl is a real catch, then a lot of guys are going to have tried to win her over. Chances are, she's gonna end up with one of them. It's very rare to find a girl like that who has been single for awhile. That's why there's jokes about "when you see her switch her relationship status to single" or "when you see she started deleting pictures of her boyfriend" followed by a picture of a guy jumping into a box or something that says "her DMs." Guys know to take their shot when the opportunity presents itself. Simply waiting until you meet some perfect girl who is also single could take a long time.

Point is, the most desirable girls probably are taken, because guys took their shot with her and one of them got her. Doesn't mean they'll be taken forever. As you get older and older, less and less girls will not have ever had a boyfriend before. You kind of just get girls after they go through a breakup. The vast majority of girls I know aren't single for more than a few months after a breakup. So that's what it comes down to most of the time.

Kinda get what I mean? Sure, the girls you like are probably taken. But a lot of them won't be taken forever. Those breakups are your opportunity.