Originally Posted by Wogster

I think a lot of it has to do with "tradition". When Tullio Campagnolo popularized derailleur shifting in the 1930's internal gear hubs were only 3 speeds, so it would have been impossible to extend the range, without adding more gears, the development of dual planet assemblies made this possible, and with each assembly being around 20mm wide, it's possible to get as many as 5 inside the hub. But multiple planets makes the translation from Bowden cable movement to planet movement a complex procedure. An electronically governed IGH would be simpler mechanically, a stepper motor could be used to move the planets, better yet each planet assembly could have it's own motor, with an ASIC to translate switch movement to planet movement. Power requirements would be extremely low, I think a pair of button cells would probably be sufficient, but a simple generator at one end, with a capacitor to ensure power when the wheel is stopped would be more reliable. Combine that with disc brakes and belt drive, and you would have 50,000 miles between drive train maintenance.

I find it interesting derailleur shifting is more popular in North America where bicycles are considered toys and sports equipment, but IGHs are more popular in Europe where bicycles are considered transportation.