There is an inability in the human mind to conceive what it would actually be like to be smarter. Therefore it is easy for anyone to believe they are as smart as it is conceivably possible to be.
This becomes dangerous when insecurity or narcissism means someone shuts off doubt and humility and is somehow able to convince people to give them some responsibility. In Trump's case "I am wealthy and therefore successful* - and I am on TV" seems to have been what worked.
The Donald's IQ... Less than his shoe size?
OK, realistically - in the 70s if he took a test. I doubt he is that mentally functional to get anything higher.
*this is doubtful, he was left a lot of money by his father and has a string of bankruptcies and massive debts.
Anyone who has accomplished something has failed on the way there. This is normal, and unavoidable. He has also failed less than the average in his business. It is deeply troubling that bitcoiners, of all people, have trouble with this concept.
Incidentally what do you estimate that Bidens IQ is? Just out of kuriosity.