Part of what drives prices of gas, food, etc., is the cost of real estate. BC is a hot market. Look at what a house costs in someplace like Kelowna and compare it to a lot of the US. Business owners have to pay for those higher real estate costs whether they rent or buy.
Here in CO, gas is averaging somewhere around $2.09/gallon. Here it's $2.27+. Up valley towards Aspen, it's $2.75. In Vail, it's $2.65. In Telluride, it's $2.95. All in the same state with the same tax. The price of real estate matters. Plus, in popular places, employers have to pay more to entice workers to stay.
We are planning on a six week trip to BC this year. Sure, we'll try to fill up before we get to an expensive place like Vancouver, but we also recognize why costs are higher there. For us, we are getting to Canada as fast as possible, only spending 2 1/2 travel days each way here in the US. If one is truly concerned about the costs of fuel, food, and camping, stick to the mid continent of the US and the south (ex. FL) where costs will be lower.
I have always been treated with such great courtesy whenever I have visited Canada and am thankful that Canadians realize that not all of their visitors from south of the border have the same views as FullTimeDaniel.