Someone mentioned how arbitrary numbers are for metro areas and I tend to agree. The method used to start and stop counting people as part of a metro or consolidated metro area is probable the worst method except for all others. It’s a metric that leaves much to be desired as older Northern Metro areas are not that comparable to many Sun Belt metro areas.
The fact that people are willing to drive 60 miles from their home to downtown Atlanta makes them part of metropolitan Atlanta. However, on the other hand, because not enough people who live 60 miles from downtown Detroit are willing or need to drive to central Detroit means that they are not counted as part of Metro Detroit. Thus, you have a case were people live equal distance from their respected core cities; yet, they are included in the metro count of one and excluded from the count of the other.
The majority of the large Northern Metropolitan areas were populated before all the super highways. They have much greater densities than the typical Sun Belt metros, but there are exceptions like Miami and many California Metros. Metro Dallas, Houston, Atlanta and others consume thousands of square miles to produce those high numbers. If you superimposed those same square miles over many Northern Metro areas, you would find that many of these Southern Areas would fall in their population rankings.
For example, the Detroit area is an international area. The Detroit-Windsor Detroit-Windsor
area has a combined population of right around 6 million people and likely covers fewer square miles than Metropolitan Dallas or Houston. Thousands of people cross the border every day going back and forth for work, entertainment, shopping ect. Windsor Ontario is as much a part of Metropolitan Detroit as Fort Worth is party of Metro Dallas. Moreover, if one added Toledo Ohio to metro Detroit, to make the area as large as that of metro Dallas or Houston in square miles, that would make the Detroit area around 6.6 million people.
In light of this, rankings are really meaningless to a large degree. What’s more important are the trends. It’s obvious that the trend is toward warm weather living. Many areas are booming also because of immigration from Mexico and not simply migration. Eventually the issue for me comes down to quality of life.