> What sort of motor do you think a Tesla model 3 uses, for example?

IPM-SynRM https://www.youtube.com/watch?v=esUb7Zy5Oio

They went into a lot of effort to optimize it over RPM range.

If you want to make a point use real motor curves at least. Your graph suggests it goes to sub 20% efficiencies at low speed which is completely false and would suggests way higher gains from gearbox than in reality. Hell, it would suggest ICE like performance, it's THAT bad.