Good valid counter points on the "big size" ref I made. I agree, dimensions are about the same between 1/2, 3/4, and 1 ton except for overall height. You have to agree that there is a heavy duty element that affects ride and overall general gas economy, except for towing in most cases. However, there is a market for those that don't require that level of enhanced structure for what they also want their truck to provide.
I tow my TT from time to time, but for the most part, its for casual hauling such as mulch, and small loads. I had a Yukon Denali which was a great vehicle but pushed the limits of my towing needs. I found my Sierra Texas Edition configured with MAX tow pkg, which includes a beefier rear end, heavy duty springs and engine management upgrades. My ride comfort is not unlike my Yukon. Even when not towing and are taking a longer road trip, we take the truck vs. the car.
The GM marketing folks saw a demand for a segment that the 1/2 ton can fill. I would love a 3/4 ton Burb, but alas, they don't make them. I've heard it may come back. Unfortunately, it may not fit in my garage which is my need. I looked for a year across the US to find my truck with my required configuration...and found it 90 miles away at a dealer. Yes, expensive but I got a good deal given the premium the Yukon Denali brought and the incentives by GM.
Not to diminish 3/4 or 1 ton trucks at all...its just a market segment that GM, Ford, and Toyota is now targeting with some very capable products.