I think this perception is out there, sometimes. But here's how I think it actually pans out. A case study of our older Lotharios.
Two former colleagues in London: in their late 30's, only dated 20 somethings (often foreigners). So could claim they were desirable to that demographic. Indeed, seemed to have some success.
But -another way of looking at it - it was more turning a predicament into a virtue - because women who were more at their level (so who "got" them and could "place" them) were phasing them out?
It wasn't youth that was attractive: it was that 20-somethings weren't socially adept enough at to recognize these guys weren't all that? Or didn't care? These younger women were seeing them as someone for attention and support who had the financial clout to take them out on nice dates. Not a realistic partner.
A 22 year old globetrotting Japanese student is not looking to have babies and settle down. So she'd be their lover, let them buy her dinner and show her round town. In THEIR eyes they had the option of these women, who were shaming all their jealous frumpy old English sisters.
But these guys weren't being taken seriously? Their young "girlfriends" would always end up "getting back with an ex" or "cultural issues, my mother won't approve of you" or having "commitmentphobe issues".
If the guys suggested maybe visiting her in her next country or whatever, they'd get blank looks.
Nothing blatantly wrong with these guys, just mediocre...so yes, they'd done Oxbridge: yes they had ok City jobs. But both had nightmare mothers, weren't conventionally masculine, and since those uni days hadn't moved forwards as their peers had?
So trying to compensate by finding a Miss Perfect to build their self-esteem, give them a dream life, protect their precious ego/feelings (at not quite being as good as their peers) and basically turn them into a man.
(All you single over 35 year old women: you've had a lucky escape, methinks).
Our two heroes? One went to the Phillipines to get a wife. One also moved abroad and got married there: he is still under thumb of his mother, and soon to be divorced and sent back to the UK (oh dear).
Still, looked happy for a while. They are both still presumably mediocre and frumpy, and the women (age/looks/nationality etc) are irrelevant to the equation.
So life goes on...