I've noticed this as well. Bigger trucks are less in demand compared to 1-1.25 ton trucks. It's made me rethink my purchasing options if/when I get my biz started, and its made me make getting a CDL a priority. The bigger trucks have more license cost but I'll already have growing room built in for bigger machines if needed. Somthing else to consider with bed options is a dumping flat bed with removable sides. One can haul dirt, debris, or lumber on the same truck.
FYI, At work the other day, we loaded 2 different orders of drywall. The guy brought a F450 with 1.25 ton hauling weight. We put 67 sheets of 4x12 on. At 90lb. a sheet, thats a little over 3 ton! The next guy had a ryder 1 ton and we loaded over 100. (I didn't get the exact #) Again, at 90lb. a sheet, thats 4.5 ton!! So, when loading, know how much stuff weighs!!