Digital effects pedals have trouble emulating the nonlinear behavior of vacuum tubes, so I imagined the same issue would come up with mechanical implementations. I've never heard a digital trumpet that sounded much like a real trumpet.
Digital implementations also often suffer from being too perfect.
You won't hear a trumpet suitably emulated by motors either. But that wasn't the question.
Any motor-based oscillator can be accurately emulated by a digital oscillator, so the answer to the original question is "nothing." But yeah, neither is good enough to emulate a trumpet played by a human.
The trumpet on my prophesy ain't half bad but yes I concede that point.
For synthetic sounds however, at this point I think it's mostly a question of workflow. Like yes you can take time to program all those imperfections into a digital sound. Or you can take time to make an analog device which has them inherently.
Indeed, motors are physical devices with their own imperfections. But … these are brushless motors, tightly controlled with a feedback loop. They, as they also say in their videos, very quickly follow input changes. I wonder how much weird effects you might hear on those.
They literally perform worse than digital oscillators, and that's desirable. Pure sounds are boring, sounds with character are what makes music interesting!
sound like a mechanical oscillator -- up until someone figures out how to emulate it, which is true of every instrument. But, here it is, and it sounds unique, and that's the point.
Digital implementations also often suffer from being too perfect.