(The National "net worth" which by the way, hit an all time high in 2015, is $84.9 Trillion. A trillion IS a million-millions. So in a country of 330 million people, our average net worth would be $257,272. If your net worth is a quarter-million dollars, you are "average". So no, even the entire wealth of the United States is not enough to give everyone four-million bucks! It also puts the national debt, of about $60,000 per person, in perspective).
Funny thing, though. Sanders has spent his whole life in government service (and did little else) and suckled on the teat of Uncle Sugar (and the State of Vermont) for decades. When he retires, he will have a fully-vested pension (if not two) and fully paid-for health care. For each $50,000 a year he gets, that represents a million bucks in the bank you and I would have to save up to retire at that level. So Sanders, even if he only has a purported net worth of "only" $300,000, is in reality a Millionaire many times over. Maybe we should tax him, first.