Virtually All Sources Are Wrong

Here is Wikipedia: Virtually all sources agree on John D. Rockefeller being the richest American in history. The second place is disputed, held by Andrew Carnegie, Cornelius Vanderbilt, John Jacob Astor IV, Bill Gates or Henry Ford depending on the source; most sources agree on Carnegie. Further places are a matter of even bigger debate. This is just silly—John D. Rockefeller was not even in the top 10 of the richest Americans, even adjusting for inflation. So that led me to wonder if Wikipedia's claim was true. Alas, I discovered it was true. Virtually all sources agree that Rockefeller was the richest American of all time (even though he wasn't even close.) The New York Times agrees. Forbes agrees. Business Insider agrees. CNNMoney agrees. How could this happen? How could virtually all sources be so wrong?