I have always bought 2WD simply because if it is snowing, I'm not pulling a trailer. In the 5 new pickups I have owned in the past 35 years, I have been stuck 3 times. The extra hardware of the 4WD is just another thing to wear out or break. Insurance is a little higher for 4WD simply because people use it to get in trouble both on and offroad. Many people believe 4WD means you can drive faster on ice and snow. Well you probably can use the extra traction to get more speed. However all vehichles, both 2WD and 4WD have 4WB (four wheel brakes) and in all the years I have lived on this country road outside of town I have seen far more 4X4's over the hill, on top of the guardrail or smashed up. This is simply because too many drivers think 4WD makes them King Kong and they drive in an over confident manner.
If I were replacing my truck today I would consider a 4X4 simply because I now park my boat in the back yard and it would be nice to have a little more traction. As far as pulling the 5th wheel I never need it nor do I pull into places that require it. So overall I would say 4WD is good if you actually have a need for it. Otherwise it does nothing for you and does not make your tow vehicle tougher or stronger. I overhead a guy buying a very large bumper pull travel trailer tell the salesman he had enough truck to handle it.....it was 4WD.