Let’s put up the real scenario....the French kept everything west of the Mississippi, and the Russians kept Alaska, western Canada, and Washington state. The US would only amount to twenty-two states today, and would never have been a world power.
That’s supposed to be a real scenario? A scenario, maybe, but real? Not by a long shot.
The French were in no condition to “keep” anything in what is now the Western United States. they did not populate it, they did not control it, and they sure as hades would not have kept it. Same for the Russians; neither country had the wherewithal to populate, control or protect any territories in North America.
How about this scenario: a Republic of Texas stretching from the Gulf of Mexico to the Pacific Northwest? That’s a scenario at least as realistic as yours.
The Russians colonised as far south as Fort Ross in northern California. Ross = Russian. Get it?