Concerning this, I would actually think that Darwin would say "yep, that's evolution in action." The only statement made by natural selection is that those which are best fit to breed do so, and pass on their traits to the next generation. If we have decided collectively, as a species, that a wealthy person is best fit to breed, then by all means they should do so. Of course, it is somewhat defeating the point if the parents can't pass down their traits to the children, but I'm relatively sure that most of the children of wealthy snobs will become wealthy snobs themselves, so there's not too much of an issue here.
However, I would also like to point out that, statistically, upper and middle class families are far more likely to have less children then poorer families. Note the rapid population booms and overcrowding in what are normally considered "third world" countries. More developed countries with a more active middle/upper class have much lower birth rates, and I've heard some even have negative birth/death ratios.
In any case, you can only look at evolution from a hindsight perspective. Whatever is more fit to breed does so and the entire species eventually becomes more and more like that ancestor. The only way you can define more fit to breed is if you take a look back and see what actually did breed more. That member is therefore the "fittest."