According to Richard Florida's post in Atlantic Cities - (link fixed)
Nashville's growth as a music center, according to my own accounting, has been explosive; since 1970 it accounts for almost all the growth in the music sector in the United States. Its resiliency and depth have undoubtedly contributed to the region's impressive job growth over the past several years.And while Los Angeles is still number one when it comes to jobs and income in the music business, Nashville is far stronger on a per capita level - and is gaining on all fronts.
Nashville has the deepest concentration of the music industry in the country. The chart below from the report compares music industry cluster jobs for Nashville and other leading U.S. music centers. Nashville has 7.8 music industry cluster jobs per 1,000 people compared to 2.8 for LA, 2.6 for Austin and 2.0 for New York.There is a lot more data and information in the article, and it shows how much better LA needs to get to keep its cultural industries from leaving. And that brings us to the one fact the article does not mention.
The reason the real growth started to take off in 1970 is that was when the Country/Western and folk music culture and industry finally left - or was driven out of - its long time home of Los Angeles.
Yes, in the 1930' - and particularly in the 1940's and the 1950's- and even partly into the 1960's - LA was the place to record and perform country and county-western music music.
But... more on that later....