I don't really get what you are saying about "120-400 being brutal" Level 1 charging is all I've had for years across multiple EVs. And now we have two EVs in the household and even then it's OK... although the other EV driver has free L2 charging at all three of his work locations so mainly I'm the one charging at home.
Most days, I just drive a few miles to work and back, and I catch back up to 80% every night no problem. If I go out of town, it can take me several days to get back up to 80%, especially since I have my home charging schedule set to only charge between midnight and 3PM which is when power is at its cheapest (and it's still not cheap, I hate PG&E, but that's a different discussion).
I've had my Tesla for 2 months now and I've used a Supercharger exactly ONCE on a day I'd driven pretty far... I didn't need to, but it costs about the same as charging at home, so I was like, why not at least make sure it works!
I don't think it would really matter if we had 800V-class EVs instead of 400V-class EVs... The efficiency difference between AC120V to DC 400V or 800V is really negligible and the cost difference in terms of onboard charging modules is likely minimal, especially at scale. In fact, the cost difference in those components can probably be offset by thinner high voltage cables between the battery and motor(s) so it could even end up cheaper to build an 800V-class EV than a 400V-class EV? I don't know enough about it but that's just an assuption.
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