My take on it is that our foot print is long, not wide. Process of natural selection has to stand for something. The rolling diameter is everything.
There are alot of old sayings that the forestry workers used on the island,
You can make thin tyres fat, but you can't make fat tyres thin.
Let's look at it in absolutes, If you had a really wide tyre, but not really high, like a can of coke, you'll be pushing sand as the tangent at first point of contact is very steep.
If you have a really tall tyre that is thinner, like a racing bike wheel, then it'll roll over easily as the tangent at first point of contact is very gentle.
Most of the MAN's i drove did go further when fitted with 1200/20's, the 1300/20's would see me carrying a tyre gauge and dropping pressures to 65-70 PSI.