You're ignoring the vehicle has to be able to carry an HVAC system on it unless you're fine with freezing in sub zero temperatures. Like where do you think all that weight is going? Car manufacturers just arbitrarily making their own costs higher and fuel efficiency worse for nothing?
If your solution to this problem doesn't account for the disabled, elderly, physically unfit, or requires that some or all people be unable to drive in weather that personal vehicles right now handle without issue, like freezing rain, you're not gonna get much buy-in.
If your solution to this problem doesn't account for the disabled, elderly, physically unfit, or requires that some or all people be unable to drive in weather that personal vehicles right now handle without issue, like freezing rain, you're not gonna get much buy-in.