The OP is right.
Power is power.
Torque is not a unit of power.
An engine producing 200ftlb @ 6000rpm will produce the same exact amount of power at that point as an engine producing 400ftlb @ 3000rpm.
What you want, unless it's a CVT type setup, is a broad power band, torque is meaningless overall unless RPM is considered with it, which gives you power.
Steam engines and electric motors have a huge power band.
Diesels are used due to longevity and the fact they produce good power down low which is useful for taking off with a heavy load. An engine producing 300-400HP between 8,000 and 12,000 RPM would probably perform fine in a tractor trailer with a good CVT setup, but it won't last.
Also it seems like "good" and "CVT" don't typically go together, but I'd love to see a computer controlled hydrostatic setup. I think it's cost prohibitive though.
Torque and RPM are similar to voltage and amperage. Overall, when it comes to work, each alone is meaningless, but combined it tells a story.
Stop concentrating on torque and passing around the old "torque matters" BS and start looking at the power curve.
Everything you need to know about an engine's performance is in the power curve. If you're obsessed with torque for some reason, it will be reflected in the power curve as others have said HP = torque * RPM \ 5252.