You have applied arbitrary costs to government intervention. There is no question that our system produces low cost subsidized food.
Ron in Regina posted (I think it was on this thread) about how the elevators in Saskatchewan were removed and fewer mega elevators have been built causing farmers to haul with larger and larger vehicles. This is partially the caused of the highways in the province (according to R in R) to deteriorate. How much damage in dollar value has this caused? The farmers aren't paying the bill. The government is not fixing the roads and tacking it onto a loaf of bread or sending the bill to the elevators. If we are going to look at the true cost of subsidies we have to look at everything.
Ok, let me play devil's advocate on this.
One could easily make the argument that having multiple (smaller) elevators in an area was the cause for more roads to be built and maintained in the first place.
Further, the 'fee' that was charged by the CWB also has to be recognized as a revenue stream.. If that money went straight to the federal gvt coffers, then the CWB was nothing more than a regional specific tax on Western growers. That said, do the funds go towards maintaining the infrastructure (roads) or does it exist as the aforementioned tax.
In teh end, the farmers were getting the sh*t end of the stick on this. They had NO opportunity to realize market value for their product, instead, the price was dictated to them... IF there is a cheap food policy in Canada and the farmers are ground zero in the production chain; and IF the price was dictated to them and non-negotiable, I will suggest that it is, in fact, the farmers that are subsidizing/supporting the cheap food policy AND they are also paying an indirect tax that could/should be applied to any infrastructure concerns.