You say this with certainty as if you helped design the chassis.
Safely is staying within all specs. Will every 1500 tow an 8k lb travel trailer within spec? If not, then you cannot say that all 1500s can. That is not something that either of us can know.
I'll leave it with this. CAN and IS DESIGNED TO are 2 different things.
Not all 1500s were designed/rated to tow 8,000 lb travel trailers where you cannot adjust the load position in relation to the axle. This is the part that is strategically left out of advertisements and a significant point that some are seemingly willing to ignore.
That rating is specific to the truck.
I disagree on operator competence. Operator competence is the driving force that determines whether or not one knows enough about what they're doing to use the truck as it was designed for. It matters.
We've beaten this poor horse to death.