There's a big difference between cities and MSAs, which the parent referred to. Using city populations like that is, IMO, almost always misleading. For the given example: hit the DFW metroplex, you're hitting Arlington. Another instance of the misleading aspect of looking just at city size: Atlanta has a city population of a bit over 400k. That makes it the biggest city in Georgia, and yet isn't even a tenth of the Atlanta metropolitan area, which has about 5.4 million people.
Top 10 US cities by population ( http://en.wikipedia.org/wiki/List_of_United_States_cities_by... ):
NYC
LA
Chicago
Houston
Philadelphia
Phoenix
San Antonio
San Diego
Dallas
San Jose
Top ten MSAs by population (
http://en.wikipedia.org/wiki/Metropolitan_statistical_area ):
NYC
LA
Chicago
Dallas
Houston
Philadelphia
Washington, DC
Miami
Atlanta
Boston
The 10th-largest MSA is four and a half million people, the 10th-largest city is just under a million.
The 10 largest MSAs contain over 80 million people. That's already over a quarter of the country -- more than the 50 largest cities put together. Taking it out to the top 20 MSAs brings that up to almost 117 million. The top 50 MSAs cover more than half the country's population.
Edit: restricting it down to "urban areas" instead of MSAs brings the numbers down a bit, but the top 10 and 20 still make up a huge amount of it ( http://en.wikipedia.org/wiki/List_of_United_States_urban_are... 2010 instead of 2011 numbers here ):
Top 10: 73.4M
Top 20: 101.8M
Top 50: 143.1M
(And as a resident of one of the largest urban areas, I would absolutely prefer more of a popular vote. But the country is much more urbanly clustered than the "top 50 cities" stat would suggest. But IMO that's a reason
for a popular vote, not against one.)