Generally the area gets bootstrapped by some major need or force that is so potent that it establishes a vibrant economy around, and if it's potent enough, even after the need has passed.

Major civics projects like damns might do this. (Grand Coulee damn along the Columbia River comes to mind.)

Ongoing jobs like military bases might provide enough logistical need. Or a factories / exploitation of natural resources (fishing, forestry, coal, iron, processing / shipping along waterways) where there's sufficient density. Sometimes it's conditions favorable for the flow of talent, like good worker protections and a rich field of jobs so that someone can settle and build resources: Opportunity that, IMO the rich have largely denied those born in the 80s and after via housing policies and investments exactly like those mentioned in the article.