If someone tells you they understand a normal combustion engine commuter car transmission they are either a transmission expert or a scammer, whereas you can make an electric motor literally with a battery, wire and some magnets.
And you can make a working multi speed transmission with a kids toy, if you're going to reduce both sides to a simplistic representation rather than just the one.
https://www.youtube.com/watch?v=IqpuJRwjCfM is a manual transmission for example.
Trying to compare the simple motor you linked to a functioning transmission is like me using that mecanno video to say how simple a transmission is compared to the motor and control circuitry out of a modern electric car. Comparing like for like I'd venture to say that most people would have considerably better luck understanding exactly how a real manual transmission works than exactly how a modern electric car motor works.
Edit: Realised that was a bamboozle and I walked right into it too...