The British government regulated the actions of the thirteen colonies as thirteen separate legal and political entities. There were no legal ties connecting them. Given the size of British America and the primitive nature of transportation and communication facilities, the absence of a single market was not particularly important at the time of the Revolution. But what would have happened with the invention of the steamboat and the locomotive? Would the British government have done anything to expedite the movement of goods and services across colonial boundaries?
There is no reason to think so. The American single market was a product of success in the Revolution and some wise judicial interpretations of the Constitution. We take it for granted today, but there was nothing inevitable about it.