The answer is <span>urbanization</span>.
Catholicism was still dominant in Europe. There were many Calvinist centers in France. Most people in Norway were Catholic. England and Scotland had the most Muslim centers.
Honestly, I think the United States would eventually look the same as it does now. If they had not bought the land, they likely would have gone to war for it. It is very unlikely that they would have let it stay there as part of France or an independent country, both because of Manifest Destiny and for national security.
In the novel, 'The Tortilla Curtain' by T.C Boyle.