We need this great new government power, for your own safety. LOL.
You mix your tenses (to your advantage, we must think). Without British protection, the Colonies must then defend their coastlines, their bays, their ports, and their frontier borders. What of the protection of colonial citizens and commerce at sea from aggressors? Primarily at the hands of the British, to be sure, but also at the hands of Barbary Coast brigands and at the hands of other potential enemies. The problem with Great Britain was a problem made worse by the distemper they suffered by their defeat at the hands of a bunch of backcountry ruffians and rustics, and from which the Brits did not completely recover until near the end of the Victorian Age (conveniently just in time to be able to count on US aid in dealing with the troubles of the Twentieth Century).
The colonies had no friends at the time of their independence, save possibly Portugal and the Netherlands. They did seem to have some who could not be counted enemies.
You scoff at the protection of this “great new government” but then I must ask you, why do you even speak of an ideal confederacy? What was the need? Why did the 13 originals not simply retain their independence and eschew any form of union? Then they could keep their freedom and not worry about coming under the thumb of some oppressive central government two hundred years later.