I take your general point, but:
> Except that it doesn't work if you don't drive your car alone (if you assume the plane is full of passengers, why not assuming that the car is, as well?)
These can be measured for averages. Lots of cars with one person in them, seldom cars fully packed; lots of planes fully packed, seldom (but it does happen) that the plane is almost empty.
> we have largely missed the goal of keeping global warming to 1.5C (thinking that we could reach it is absurd at this point).
Probably, yes; last year passed the threshold — it would be a pleasant *surprise* if that turned out to have been a fluke 14* years early.
* 14 because it would take 14 years for the exponential — seen for the last 30 years — for PV to replace all forms of power consumption; not just electricity, everything. But even then we'd also need to make rapid simultaneous progress with non-energy CO2 sources like cattle and concrete.
> around the equator will become unlivable for human beings (similar to being on Mars: you need equipment just to survive outside)
In so far as your bracket, sure; but there's a huge gap in what equipment you would need.
The comparison I often make is that Mars combines the moisture of the Sahara, the warmth of the Antarctic, the air pressure of the peak of Mount Everest, and the soil quality of a superfund cleanup site, before then revealing that it's actually worse on all counts.