It is a perfect sentence. Whether it is correct or not, I do not know. However, it is grammatical and its meaning is clear. The word "capital" (note lower case "c") is an economic term that means "accumulated savings". It usually refers to money, but it is really broader than that. It sometimes includes all forms of asset such as land, labor, skills, and education. The meaning of the sentence is that when the U.S. built its industrial foundation, it started from scratch (from nothing). There are countries today that have depleted all of their capital. Argentina is a good example. Perhaps Argentina may turn around some day and rebuild from (close to) zero. I choose to believe that it is possible for them to do so if only they make the right choices.

Capital can mean the main city of a state or country, but it is also a term in economics. I took a quick look at a definition, and capital can also mean wealth, sometimes in the form of money, sometimes in the form of other resources. In this case, the sentence is saying the US didn’t have the money to build up its industry

The sentence is poorly written and contradictory. If it successfully built its industrial foundation, it must have had the resources, including ‘capital’ i e money to do this. It could be intended to mean that there was insufficient capital to do it properly, but this should be made clear, for example, by saying ‘sufficient capital’ or adding a word like ‘effectively’ at the end of the sentence.

No, it's just another meaning of the word capital. Here's the definition Google gives: "wealth in the form of money or other assets owned by a person or organization or available for a purpose such as starting a company or investing."