[Ecky]

One perspective is that RPM is really just the number used to determine the relationship between engine torque and vehicle weight. If you have a heavier vehicle but the same engine, you'd need more RPM for it to drive the same. Conversely, if you put a bigger engine in your vehicle, you need to reduce RPM for it to feel the same, and for the engine to be similarly loaded. But, this is why you have a set of different gears to choose from. And you can't directly compare RPM of your truck to that of a Civic in a given gear.

Lowering RPM has a very similar effect on economy and feel to downsizing the engine.

EDIT: A great example is the 2018 Corvette. It weighs 3600# - more than your truck. Its rear axle ratio is 2.41. 8th gear is a very tall 0.65. It has big tires - 20 inch rims, in fact. In top gear it's able to cruise along at 1330rpm @ 65mph. It's a very fast car, but some have reported seeing upwards of 40mpg on the highway despite having a monstrous supercharged 6.2L engine. It can still accelerate well in lower gears, but it's nice top have that top gear and tall final drive for relaxed, efficient cruising.