But the only reason "price by fiat" works is because the Canadian government has the authority to set a price ceiling for a huge number of buyers. UHC doesn't have the same market power, because it's competing with other insurers who can potentially cover the same people. If Canada decides that a drug is worth no more than $X, there is no way to sell to Canadians without agreeing to that price. If UHC decides a drug is worth no more than $X, in the short term you can't sell to UHC customers without agreeing to the price, but in the long term you can exert leverage over UHC because people might switch to other insurers who cover more drugs.