How are the enlightment ideas that influenced the founding fathers reflected in modern institutions

Why did leaders such as siddhartha gautama abandon hinduism to createbuddhism around 500 bce:

By the end of the 1800s, there was a change in the nature of the immigrants coming to the united states. immigration from northern europe—england, ireland, germany, and scandinavia—declined, while immigration from italy, russia, and austria-hungary grew. in fact, between 1900 and 1910, more than three-fourths of all immigrants came from these three countries. unfortunately, these countries were far removed england, the home of our founders, and the immigrants who came from them had a hard time adjusting to life in their new country.

Ahistorian who compares the expansion of political systems to the expansion of economic systems is organizing history by