Originally Posted by
larrytherider
The complication is not exactly the derailleur itself. A derailleur implies stacked gears, and that the chain has to be shifted sideways, off the plane that it should operate in; and if you pedal with force during gear switches, you may damage the chain links. All these imperfections combine to make a derailleur based bike design not so ideal. Wouldn't it be more ideal to have a design that gets rid of all of the above?
To some degree yes, but gear box type transmissions already exist. Think of it in terms of an automobile transmission. Automatic may technically seem better but with complication comes cost and durability issues that standard transmissions don't have.
Yes, you can damage a chain or gear when shifting wrong but that holds true for a standard auto transmission also. You can grind those gears if you don't use the clutch and accelerator properly.