I recalled a conversation with a client that I worked with - it's a casual chat.

He asked me if I have a girl friend, and I said I don't.

He asked about my age, I said I'm 25 (last year)

Then he said:

"No worries young man, I had the same situation like yours - but I was married at your age"(which is quite normal, back then)

"What I mean is, you'll find that you are 'not so attractive' in the 20s, the ladies didn't quite bother to talk to you... etc"

"But entering the 30s, if your job is good, and if you have the family that gives you the stability - that's when you'll see the ladies 'attracted' to you"

"And I can tell you, it'll be irresistible"

That, explains few things:
1) Why men after 30s can be even more flirty
2) The ladies who look for those 'stability' - are what those men in 30s or 40s can offer (regardless if they have family)
3) Men at 20s, if you find yourself 'unattractive', please work hard, at least there's a hope starting from 30s?

And the bad cycle continues.

To me, I'd say - "If there's a demand, there will be a service"