Agree with your whole post, but responding to the above quote, I just want to say that having a road charge program allows for scaling charges at least somewhat more fairly than the status quo. As you note, there's no way to charge a 10,000x premium for mileage driven by 18-wheelers, but once we know the mileage driven, that data will be very useful. It'll be possible to quantify the liability more fairly and at minimum make more people aware of the points you raise.If they are looking at costs in comparison to damage caused, then it should be noted that just one 18 wheeler causes the same amount of damage as 9,600 passenger vehicles.
Currently, we all subsidize it with our taxes, and get it back to some degree on the cost of goods at the supermarket/warehouse store/Amazon/whatever. Obviously if the transportation taxes become higher on shipping vehicles, it will raise prices. However, it will also level the field with other competing transportation methods (rail, as you mention).
I volunteered because I really think a mileage based road charge is the best way forward. We'll see how it goes.