1. Trump was born wealthy. There was no "arrival of wealth" that smothered the intelligence you suppose he might have used to earn the wealth, because he didn't earn it.
2. You don't understand. Trump is successful because of his stupidity, selfishness, and vile behaviour. Not despite it. In 2016, the Republican primary field had 20 or so candidates on a wide range of reasonableness. Trump crushed them all, because he most represents the average Republican voter. If he were more intelligent, or if he cared more about anyone other than himself, they would not have voted for him. His arrogance, lack of intelligence and morals is quite literally his strength because it's what makes him so relateable to the American masses.
There are two possibilities. One is that half the country are total idiots and the people leading them, and leading the country, are also total idiots who only got into power because half the country are, again, complete idiots below average intelligence.
The other is that you are in a bubble and have been convinced that the leadership of the world’s premier superpower are below average intelligence, along with 70-80 million voters. The former is not something an intelligent person would believe, you have thrown out serious analysis for political theatre and memes and should rethink how you view the world. Now stop to consider that maybe actually half the country has a totally different worldview, and that their leadership, having reshaped global politics, is actually full of intelligent people who are cold and calculating. I know it’s harder to stomach, but just consider it for a moment.
This is simply a false dichotomy.
Being propagandized into extremism does not require anyone to be a total idiot.
Everyone is susceptible to propaganda and populism.
Someone like Trump isn’t the first rise to the top of the country and be a con man or be as mad as a hatter in the end… He will not be remembered for his brain power.
I think he will be remembered for the decline and the loss of influence by America across the world that will be his legacy.