Interesting observation...
Yet, if someone wants to marry young Asian woman, marrying SP maybe attractive option but not the only one.
I did an experiment. I created very average, very basic account of 57 yo guy from Toronto on
AsiaCharm.com website. In one day (!) I received more than 400 messages from Asian women in age range from 22 to 63. Many of them are really beautiful, university educated, speak English. And I got impression some of them would marry me without even personal meeting LOL.
I deleted my account on the second day.
First, the pictures are likely very photo-shopped, and other claims such as fluency in English, tend to be greatly exaggerated.
But it is true, there are loads of women in China who's only hope of marriage is with a foreigner.
If a woman in China is not married by the time she's 27, then she becomes one of the lost women. There are millions more guys in China than women, but the former will not marry women older than they are, and women will stay away from guys who are less wealthy than they are.
Many marriages are still arranged over there, especially if the woman is approaching 27 years. But there are lots of women who have missed the boat because of their career, such as university educated professionals and bureaucrats or business women. Beijing is full of them. Their only recourse is the dating agencies. Most single men over there want a woman younger than he, especially under 28 and not financially independent (richer than he is).
Then there are the loads of divorced women. Once divorced, especially with a kid, she is usually completely shut out of the market. But they know that that's not such a big deal with foreigners. The divorces come about as a consequence of loveless arranged marriages.
Chinese women tend to keep their shape and looks longer than western women. They tend to be more feminine, and in my humble opinion, tend to be more balanced psychologically, and raised in a more traditional manner. They like Westeners better because we don't usually treat them like shit, while white guys like the traditional attention. I know of white boy/chinese girl marriages that are bliss.
The downside is the culture: the food is very different and it takes a lot of adjusting; the house is going to look very Chinese. Then there are the in-laws, who will practically try to move in. In China, loyalty to parents is more important than loyalty to spouse. Language is usually a problem, and fluency in English is usually greatly exaggerated; however now, they can talk into their smartphones and get an instantaneous voice translation.
But it shouldn't be too difficult to find women who are smart, friendly, and attractive. Many who advertise want to get out of a rut, and are not that selective about prospective western partners.