Branson did not start the actual music. It had been there long before it got famous for it.
OK, famous wise maybe, but we were not far behind.
1964: The Baldknobbers music show moves into a downtown Branson theater.
1967: The Presley family opened the first theater on "the Strip," Hwy. 76.
http://www.branson-missouri.com/history.asp
Johnny Rion
He was born in Farmington, Missouri.
In 1937 he did a Saturday night radio program singing live on KFVS Cape Girardeau Missouri and began a radio career that spanned 60 years.
Johnny also had his songs recorded and released by:
Ernest Tubb
Go Home
etc...
http://www.hillbilly-music.com/artists/story/index.php?id=13505
Hank Williams..."He sings more sincere than most entertainers," Williams explained, "because the hillbilly was raised rougher than most entertainers. You got to know a lot about hard work. You got to have smelt a lot of mule manure before you can sing like a hillbilly."
http://muse.jhu.edu/cgi-bin/access.cgi?uri=/journals/southern_cultures/v009/9.2huber.html
And the Ozarks do run up through the middle. So maybe not as important, but still in the running.