I don’t think that It has much to do with motor/drive efficiency. I suspect that it’s the battery performance which is highly susceptible to excessive discharge rates when accelerating hard.
The discharge rate, even for something like a Model 3P, is pretty trivial. 20 years ago I was building battery packs that would happily support a 20C rate of discharge with no problems or cell overheating. A Model 3P, at absolute max power, is not even hitting close to half that.