I think last link is the wrong data to use. Despite the title of the article, it is using the largest possible "Combined statistical area" that contains the city, rather than anything commonly known as the metro area.
> A combined statistical area (CSA) is composed of adjacent metropolitan (MSA) and micropolitan statistical areas (µSA) in the United States and Puerto Rico that can demonstrate economic or social linkage. The OMB defines a CSA as consisting of various combinations of adjacent metropolitan and micropolitan areas with economic ties measured by commuting patterns.
For instance, the "Washington-Baltimore-Arlington, DC-MD-VA-WV-PA Combined Statistical Area" (which is not part of the top 5 cities) includes all of Hampshire County, West Virginia
For the ~70 million figure, see here:
https://en.m.wikipedia.org/wiki/List_of_metropolitan_areas_o...