I live in a world of extremes:
-67*C with windchill (-40*C base)
+45*C with humidex (+40*C base)
8 hrs sunshine in winter to 16 hrs in summer.
If I kept any type of food in the car kit, it would have to be cycled out at least once a year. I see canned goods as no better than MRE/IMPs, actually they would be less usefull in the winter except as weapons to ward off Yeti.
I've given up trying to store water during the coldest months as I would need seveal heaters to melt it in the winter - either that or put them on a hot running engine!