From the web site:
We had the NGF's research arm analyze the 50 largest metropolitan areas in the U.S. We then graded each on:
1. Weather: How much sun, rain, snow, etc.
2. Affordability: Median green fees of public courses, in relation to the median household income
3. Quality of courses: The best courses in the best overall condition
So you had to be in the top 50 population areas to make the list. Then they shuffled them up. Which would explain, I guess, the absence of places like Tucson and Duluth.
I'm joking about Duluth. I think it was Golf Digest that declared my home town America's best golf town a few years ago. Even if you include Northland (private), it was a stunningly bad choice. There is no other course besides Northland that you'd ever want to play, the weather is abysmal, and it's still tough to get a tee time. (That said, a round at Northland in August is usually as close to golf heaven as you can get in the Midwest.)