>>2060682Honestly I don't see why they don't just put the whole cassette in the front and the "derailleur" is just a spring-loaded arm that only moves on one axis. 99% of crappy off-the-rack bikes never have all their gears used anyway. Literally just make every bike a 3 to 5 speed and call it a day.
ESPECIALLY if they're electric or pedal-assisted.
Though speaking of, I saw a thing on hackaday of someone using "electric transmission" -- the pedals crank a dynamo, and the wheel has a motor. You crank the dynamo, the motor on the other side moves. Only a very small battery more as an extra big smoothing capacitor than anything. It's probably horrendously inefficient, but now you don't have to deal with a derailleur, I guess.