Most of them, since Eisenhower anyhow, are rich when they get in there. The guy who is governor of Florida spent millions of his own money to get the job ..... as did Bloomberg in NYC. Perhaps it is a thirst for power, fame, immortality via the history books ? Bill Clinton certainly got rich as a result of being president. The Lincoln bedroom was like a suite at the Holiday Inn IIRC. His speaking engagements since his time in office have certainly added to the coffers.

Years ago a friend of mine became business agent for the ironworkers union we belonged to. He and I had often complained of policies of previous biz agents. He told me that once in office he couldn't believe the perks.... outright bribes the contractors offered for special favors and consideration. I joke that whoever runs for president should be disqualified because they have to be insane. There may be an element of truth to it. If not insane, egomaniacs.