The funny thing is, that 'heavy duty' badge is deceptive marketing, pick-ups at their heaviest are medium-duty, maxing out at class-3 with a GVWR between 10,001 and 14k lbs; true heavy-duty rigs are class-7 and class-8, with a GVWR between 26,001 and 33k lbs and 33,001+ lbs respectively, and those need a CDL to drive.

For further reference, the heaviest weight class you can get away with on a normal license in the US is class-6 with a GVWR between 19,501 and 26k lbs. Pick-ups are class-1 through 3 with GVWRs ranging up to 14k lbs, medium-duty chassis-cabs are typically class-3 through 6 with GVWRs ranging between 10,001 and 26k lbs, and heavy-duty rigs are class-7 and 8 with GVWRs ranging between 26,001 and 33,001+ lbs, which need a CDL to drive, like I said above.

But I guess selling pick-ups as their true weight class doesn't move as much units as the deceptive 'heavy duty' badge on a light-duty or medium-duty rig.