We RV'd with "ice boxes" before the 110v/LP fridges came on the market. It wasn't possible to take along much prepared food or food requiring proper cooling or frozen foods.
The LP fridge opened up the possibility of traveling with frozen foods and other prepared foods/etc. Fridge makers advertised that fact over the old "ice boxes".
I can see where folks in Canada may choose not to use the fridge when making long trips however down here it gets to 115+ degrees and even hotter on a asphalt road.
Now we can travel with the fridge on and know our food is still frozen and cooled properly/ice in the freezer after a all day run. RV trips on the road any time of year is so much easier now days.