In the pleasent book "The two Georges",Harry Turtledove and Richard Dreyfuss tell about a timeline in which the thirteen Colonies
never have secede from United Kingdom,and remain part of British Empire as Dominion.
I think that veryone that love alternate history stories have read the book,and knows how the world of two Georges is different from our timeline.
French revolution had not occurred,we have not Napoleon,or world war I or II.
In 1990s techonlogy is at the same level of 1939,or so...
But my question is this:
In "The two Georges" Dominion of North America have the same area of the United States of America of the our timeline;
Now i think that this is very,very improbable.
In your opinion in a timeline similiar to "The two Georges",
which would be the more likely size of the British North America in late XX century?