What wkwillis said of the aristocracy is half true. Division in the South between rebels and loyalists was split down the middle, with loyalists significantly outnumbering rebels. These loyalists hadn't a Canada to run to, unlike their Northern analogues. They were simply stuck with a country they never wanted. But the overall majority, in all regions, didn't really care at all, so long as the Rebellion adversely affect them. The people favored which ever side was occupying them. Everyone's true loyalty, if they had any beyond their own persons, was to their own colony.
Remember, a colony isn't an extension of a country. It is a new country. It starts under the control of the same state as the mother country (BTW, "country", "nation", and "state" are very different things in my reckoning). They are usually established to create willing and predictable trading partners and eventual military allies. Often, the colony would be absorbed into the mother country, especially when there was a land connection. In these cases, that may have been the purpose of the colony (to be absorbed), and it might never even be seen as a colony or seperate country. US, Canadian, and Mexican "territories" are examples. They are not part of the country, even if the intent is to eventually bring them into the federation. Of coarse, current US, Canadian, and Mexican territories appear to be in limbo right now, but current events tend to be. In thassalocracies, the colony is created with the intent of eventually becoming sovereign. In the ancient Mediterranean, Phoenician and Greek colonies were independent practically as soon as the ships left the dock. Despite being seperate as states and as countries, colonies and motherlands were of the same nation, so they were usually very friendly. Which, again, is the whole point: creating new polities disposed to being trading partners and military allies can be easier and more predictable than turning a different polity into a tp and ma by diplomacy and/or force. Of coarse, sometimes the border between colonialism and imperialism blurrs, as it did with the Carthaginians, Romans, 16th cent. Spanish, and 19th cent. British and French.
Where was I going with all this? The Colonies were going to achieve independence anyway, they were eventually getting too populous and would've been more efficient tps and mas to Britain as independents. The when, how, and how much didn't have to turn out as it did. Why hasn't anyone suggested thirteen republics? They were created as thirteen different countries and willing (sort of) merged into federation to maintain economic solvency. The retired general was a the linchpin in convincing the thirteen country-states, especially the southern ones, that more was to be had together.