In his discussion of "cryocrastination", AndrewH makes a pretty good point. There may be some better things you can do with the money you'd spend on cryonics insurance. The sort of people who are into cryonics would probably accept that donating it to the Singularity Institute is probably, all in all, a higher utility use of however many dollars. Andrew's conclusion is that you should figure out what maximizes utility and do it, regardless of how small a contribution is involved. He's right, but I want to use the same example to push a point that is very slightly different, or maybe a little more general, or maybe the exact same one but phrased differently.
Consider an argument frequently made when politicians are discussing the budget. I frequently hear people say it would cost between ten and twenty billion dollars a year to feed all the hungry people in the world. I don't know if that's true or not, and considering the recent skepticism about aid it probably isn't, but let's say the politicians believe it. So when they look at (for example) NASA's budget of fifteen billion dollars, they say something like "It's criminal to be spending all this money on space probes and radio telescopes when it could eliminate world hunger, so let's cut NASA's budget."
You see the problem? When we cut NASA's budget, it doesn't immediately go into the "solve world hunger" fund. It goes into the rest of the budget, and probably gets divided among the Congressman Johnson Memorial Fisheries Museum and purchasing twelve-thousand-dollar staplers.
The same is true of cryocrastination. Unless you actually take that money you would have spent on cryonics and donate it to the Singularity Institute, it's going into the rest of your budget, and you'll probably spend it on coffee and plasma TVs and famous statistician trading cards and whatever else.
I find myself frequently making this error in the following way: a beggar asks me for money, and I want to give it to them on the grounds that they have activated my urge to help people. Then think to myself "I can't justify giving the money to this beggar when it would help many more people if I gave it to a responsible charity." So I say no, and forget all about it, and never give the money to anyone. Even though (from a charity point of view) I know of a superior alternative to giving the money to the beggar, I would still be better off just giving the beggar the money!
All this means that for any entity that does not use its resources with maximum efficiency, the opportunity cost of spending a certain amount of resources should not be calculated as what you'd get earn from the best possible use of those resources, but what you'll earn from the use of those resources which you expect to actually occur.
But the economical and social situations are different in rich countries. In a poor country many people are poor, usually because there is something keeping them poor, be it war, famine, government oppression, societal oppression, or something else. In such a country this argument works: you have to make begging so economically unattractive that few people would do it because they could make more with less effort by overcoming whatever problems are making them poor. Not to mention that if too many people become beggars the begging industry might collapse because there would be too few people producing things for the beggars to buy.
In a rich country, there is a strong social stigma attached to begging. Some cultures make exceptions for beggars with particular obvious reasons for begging (injured war veterans, orphans, etc.), but to my knowledge no rich society considers it acceptable for a person who could earn a living by other means to beg. And, being humans and not "economic men", the people in those societies feel that pressure and will go to extreme measures to avoid begging, including resorting to theft (albeit a career choice made possible by having a large population with enough money to have things worth stealing). So in a rich society it probably actually doesn't hurt to give money to beggars, and may even help because it might make begging attractive enough to overcome the social stigma that pushes some people to commit crimes.
That's my armchair social analysis. It feels like it's at least a shadow of reality, though, if not more.
..."Making them poor?"
Poverty is the default condition of most of humanity for most of history. It would be more accurate to say they have a lack of the conditions for becoming wealthy. Not to say that war, oppression, etc don't prevent the necessary conditions from forming.