Excellent thread. (though you should spell/grammar check LOL)
I have had no issues with my Tundra but if my input will help get Toyota off it's ***, all the better.
Fact #2- Toyota sells a "Bed Extender".
Quote- "Extend the carrying capacity of your bed for big loads or create a small enclosure to keeps items from rolling. Made of an aluminum alloy with a quick release hinge and locking latch that prevents theft".
Source-
Toyota Tundra Truck Accessories
Conclusion- Toyota facilitates and expects the carrying of big (heavy) loads on the bed/tailgate without failure or damage.
KeyWasted