nope we would have won without them, US supplied billions of dollars worth of guns, ammo, tanks, planes, explosives, gun powder, fuel, food, clothes, radios, and other stuff to the UK in WW2 and without the US UK would have lost to the Germans
dont act like Britain was alone in the revolutionary war, Britain had help from the Germans, the American Loyalists, the Natives, and the Canadians and you still lost