In regards to the half ton towing wars, almost nobody has a truck in real life configured for the max tow rating.
Like who is running out buying a regular cab Long box XL 2wd just to brag their truck can tow 12xxx lb?
Once you start getting above 10k, If you are towing that with any frequency, you should probably be considering something other than a half ton.
12k max towing is plenty for the Tundra.
As far as giant grilles for heat transfer, there are other ways, but increasing surface area is easy, and probably cheaper if that is the route taken.
Same reason high SEER AC and Heat Pumps are ridiculously large compared to lower SEER units, cheapest and easiest way to get better heat transfer. And if all the rage is giant grilles, Toyota kind of has an excuse to follow suit. Perhaps the focus committee poll giant grilles as a positive feature