Trump was never actually broke, but his popularity comes from the fact that he took a bunch of public political stances that his political opponents refused to take because they genuinely thought those stances were immoral; and then won elections based on those stances because a lot of the electorate also liked them.

There isn't actually one monolithic class of billionaires that all share the same interests and want the same things; and even though an individual billionaire can be personally influential, they simply do not have the power to unilaterally determine the political direction of a country. But regardless of what political direction a country does go in, there's probably some billionaire who is more or less aligned with that direction. So anyone who dislikes that political direction can point to the nearest-ideologically-aligned billionaire and blame them for influencing politics in that way, despite the fact that if the tables were turned and their side was winning, someone else would point to whatever billionaire aligned with them as an evil influencer.