Stiffer frame, longer wheelbase, stronger suspension, overloads, and factory LT tires for starters. You can retrofit some of these things onto a half ton, but a lot comes down to frame design. 3/4 and one ton trucks have thicker metal, more crossmembers, larger crossmembers, etc.
My last truck was a 2014 F150 with air bags and LT tires. I had a 7600# 30' TT that I pulled behind it. I was speaking from my personal - and yes, anecdotal - experience. I had EzLift and BlueOx before ProPride and only the ProPride could keep it grounded in 40mph wind gusts out in West Texas. It would handle decently on a highway with the lesser hitches, and even when a semi passed, but you have to account for adverse conditions. Even on main highways in fair conditions, I had far too many white knuckle moments with that setup. Can't think of one with my current setup. The Propride 3P was a gamechanger, though, so I would consider that kind of rig again but only with a 3P.