THE WAIT: 46 years
WHAT TOOK SO LONG? The all-conquering original was so massive it would have been an unwise studio that dared consider making a sequel. So it was almost half a century before Disney (which owned the rights) considered a follow-up. (another factor was that the copyright expired in less than five years).
However, the sequel - which took a much darker tone and realistic approach to Dorothy's life on the farm - was an uneasy ride. Director Walter Murch was fired and it was only George Lucas's intervention that saw him return to the project.