And that is coming from the owner of a 1/2 ton Silverado.
1. Plenty of trucks have independent read suspension, including the new F-150 lightning. Heck, even the new Silverado is rumored to be getting it soon
2 & 4 - off roading is a minority use case for trucks. OEMS know that 80% of owners with 4wd never actually go off-road.
3. Even the ford f-series ('61-'63 F-100 and F-250) were unibody. Is it rare? yes. Does it have structural disadvantages for towing, payload, and other truck stuff? sure. Still doesn't settle the issue in my book.
If you want all the capability of a half-ton 4wd, knock yourself out. But let's not pretend that it's the best choice for every use case