Ron operates a garbage pickup business. He contracts to pick up garbage from an apartment complex for the next 52 weeks at a price of $150 per week. Unexpectedly, the landfill center where Ron takes the garbage to dispose of it, files for bankruptcy. As a result, Ron must travel an additional 100 miles to the nearest landfill center, turning Ron's expected profit into a loss of $40 per week. Ron's best argument in support of his petition to be discharged from the contract is