No. I absolutely do not believe this. There are a number of reasons for this, of which I will discuss two:
- People who are well-off tend to do better in school because they are born into situations where they are exposed to more books, more intellectually stimulating activities, etc. This means that they are more educated not that they are more intelligent.
- Relatedly, they often start higher up the socioeconomic scale. If you take two people of similar intelligence, it stands to reason that the one who starts out richer will end up richer simply because they got to start from higher up.
The first of these means that well-off people seem more intelligent because they are better educated. The second means that they can get richer without being more intelligent. This indicates to me that the rich are no more intelligent, on average, than the rest of us.