At worst I think this is a depressing reality and something many women are resigned to, as the least worst option for them. But whereas we like to hand wring over it and imagine them all to be like helpless little Cindarella figures, the women themselves I think are often much more shrewd and pragmatic than we give them credit for.
However, there are many scenarios that are not quite as cynical as this. As a rule, women (even women who are not poor or lacking in options) want men who are successful. Even a financially self-sufficient woman often looks for a man at least as successful as she is, and would prefer it if he were, given the choice. We see it all the time on MN, women complaining that they are the main breadwinner and they've started to resent their DH for not being ambitious enough, happy to coast along, riding on their wives' coat tails. Whereas you rarely see a man say the same about his wife. If she's been at home bringing up the children there is less pressure or expectation for her to jump straight back into the job market and to make sure she is 'pulling her weight' by matching his earnings.
Men care less about that. When most men are on the lookout for a life partner, her being able to offer him financial security and an escape route from a life with few opportunities isn't usually high on his list of priorities. Unless he's Gambian, Egyptian or Tunisian of course.
The difference is that with foreign women from relatively poor backgrounds I think there is a greater chance that they are genuinely seeking a partner they can love and can stay with. For a start, with younger women and older men they are able to have children together.
Whereas, with these men who target lonely middle aged or elderly white women, I think they are far more cynical and predatory than pragmatic. Obviously there can't be any children resulting in those marriages, which is one of the biggest red flags. Once they've got their visa or leave to remain, I doubt very many of them stick around for long.
I know a man in his early 50s married to an Filipina woman of 35. He didn't go down the 'Thai Bride' route to meet her, but nevertheless their relationship does fall slightly into embarrassing cliche territory on his part. He was married to a British woman and that ended in divorce after 20 years. He's normal, intelligent, attractive, very pleasant company, not in any way creepy or exploitative. He could have found a more 'equal' British woman to marry him very easily, I imagine. He has quite a lot of money. But he happened to meet a Filipina and the rest is history. I doubt he deliberately set out to find and marry a Filipina, but I am almost certain that she would have been casting her eye around for white western men to date. It's like a lot of the WAGs who end up with rich footballers, or groupies who target rock stars. It doesn't happen by accident. It happens because those women often make it their life's work to put themselves in the same social spaces as them, in the hope of meeting.
For my friend's wife, she's clearly won all the lotteries at once. No doubt about it. But she genuinely loves him so she's not compromising herself in any way in order to have a taste of the high life. Far from it. She's living the dream in every way, including in the relationship. And he is very, very happy, even though he must know that some people will look at the two of them together and immediately make some unpleasant assumptions.