I'm going to blame the ham radio antennas and bike rack ;)
But in all seriousness, I was getting slightly better mileage when the car was new 6 years ago. It has declined a bit, despite my regular maintenance, but I'm still very pleased with it. It might be more than twice the mileage of the average truck on the road, to be honest, but I find it hard to get a clear number. I think some truck owners embellish the mileage they actually get, as does the dealer sticker on the new vehicles for sale since those numbers assume perfect terrain with no traffic, last I checked. Then I hop into a co-worker's 2020 truck and realize he's getting 12mpg on a good day and nearly have a heart attack.
My vehicle gets between 45 and 55mpg on average, depending if I'm on the highway a lot or more urban environments.
As you say, they are absolutely terrible for work use as well - Japanese kei trucks famously have larger beds than some common US pickup trucks, and the size of the custom beds we use in the EU makes the US ones look like absolute kids toys - but that too I wouldn't mind too much if they were just forced to be safe and with decent emissions so the idiocy mainly affected the driver and their wallets.
I'm not too impressed with your vehicle only getting twice the gas mileage though. I'd expect more than that. :P