It is not about sharing road costs. It is about finding state revenue.
In CA 15k lb registration comes with about $500 annual "weight fee"
Same truck in NV has weigh fee = 0
(than NV will hit you with Government Service tax)
The trick is that you can not have truck registered for less than its GVW (you can and should more if you pull trailers).
So the truck doesn't have to be actually scaled to get a ticket.
All it takes is for officer to compare your registration to door sticker.
That again, will be different in different states.
