Although the Chicago Cubs last won the World Series in 1908 they continued to field good teams winning seven National League pennants over the next four decades. It is believed that the Cubs misfortune began prior to the Game 4 of the 1945 Series against the Detroit Tigers in what has become known as "The Curse of the Billy Goat."
William "Billy Goat" Sianis, owner of the Billy Goat Tavern, brought his goat Murphy to Wrigley Field and was refused entry into the ballpark. Sianis was so enraged he proclaimed the Cubs would never win again until the goat was admitted. The Cubs lost that game and the Series have not been back to the Fall Classic since.
But now questions have been raised as to whether the 1918 Chicago Cubs threw the World Series against the Boston Red Sox. The Chicago History Museum recently came across a deposition from Eddie Cicotte, one of the eight members of the Chicago White Sox who were banished from Major League Baseball for throwing the 1919 World Series against the Cincinnati Reds. Cicotte and the others would be forever known as the Black Sox.
In any case, according to the deposition given by Cicotte in 1920, the idea for throwing the World Series came because a member or members of the 1918 Cubs had been offered $10,000 to do so. If it's true then perhaps this is the reason the long suffering Cubs haven't won a World Series in over a century.
However, I think all of this is rather unlikely. Now I don't discount the possibility gambling interests approached a member or members the Cubs to throw the World Series but I don't think they went through with it. If the Cubs had thrown the 1918 World Series how could it have been kept secret for over 90 years? The undoing of the 1919 Black Sox was that those involved (whether they played or betted) couldn't keep their mouths shut.
There are many reasons the Cubs haven't won since Teddy Roosevelt was in the White House but I don't think this is one of them. There are other more compelling reasons such as their "college of coaches", trading Lou Brock for Ernie Broglio or Leon Durham's wickets. It hasn't stopped me from picking the Cubs to win it all this year.