I am from Sweden. I have been to Boston and NY many times. I have tried to read up on American history. But I still marvel and can't get my head around the practicalities of building a city like Boston or NY, so fast and out of "nothing"! When people came to this "new continent" what did they bring first? How did they start? Where did they get the resources? Just as an example, a lot of steps are required to make iron. You have to have a mine, it needs to be excavated, there's smelting, casting etc. Again as an example, did people bring ready-made goods over from Europe or did they build out the whole process from the start? How? Reading tips welcome!
Massive natural resources
Lots of land to support a large population
The "Old World" sent over tools and technology to succeed
We definitely didn't start with stone tools. We had that technology/expertise imported/immigrated into our country. Combine all that together, and we get the resources AND the land (thus the capacity) to build a country up quickly
The natural resources were here already. Massive numbers of people came from Europe, Africa, and Asia. The colonists brought skills, knowledge, and technology from the "old world."