They are also the ones the News Media gives the most air time to.
The rich candidates know the members of the news media. That's just natural. A lot of the prominent news media actually come from affluent families. When I lived in NYC, I worked for a corporate law firm with many senior partners who come from old money. And I did know of at least one senior partner who's son works as part of the news media.
Even Anderson Cooper of CNN is the son of Gloria Vanderbilt.