IDK if I am saying this correctly, however, it's the way I understand it.
Small/mini trucks must meet a certain EPA Fuel Economy & Emissions figures. The size of the truck determines how the manufactures reports these figures to the EPA which is why small trucks are getting larger with each generation/redesign. As are our new vehicles in general. As you can see, most all vehicles are getting larger with each generation in their respective segment. And that's because(the way I understand it), the EPA regulations are always changing...depending on the size of the vehicle, the EPA numbers change. So manufactures are being forced to make vehicle just that little bit larger in each new generation/per segment or meet an even hight fuel economy & emission figure.
The way I understand it, for those older sized mini pickup trucks in todays market, in order to meet EPA fuel economy & emission figures, might have to be so underpowered that they'd be a terrible truck.
And the same for cars/SUV's. Compact size today was Midsized just a decade or so ago. And so on!
My daughter's '22 Civic for example, is as larger or larger than some of my older Accords that I've owned.
My '23 Venza is a larger Compact than my '01 RX300 was as a MidSize. Coincidently, both are Toyota Harriers...just saying!