He was not super rich. He was worth more than I am, but not by much. He was not even close to Trump. And Trump’s wealth makes him pretty much immune to bribery or influence from campaign donors. That is what the left hates the most.
You’re right - it’d be almost impossible to ‘buy’ President Trump.
http://time.com/money/4041300/donald-trump-has-more-money-than-every-u-s-president-combined/
“In fact, a President Trump would not only be the richest president in U.S. history; he’d be richer than all previous U.S. president combined. (Their collective net worth adds up to only around $2.6 billon.)”