R147 the early white rock and rollers such as Elvis, were specifically called rockabilly singers because it was connected to country. The Rock & Roll hall of fame includes numerous Country performers under their early influences inductions, including the very first early influence inductee Jimmie Rodgers, as well as Hank Williams Sr., Bill Monroe, and Bob Wills and his Texas Playboys. In addition some of the regular inductees that had Country, as well as R&R, careers include Elvis, Bill Haley, Buddy Holly, Jerry Lee Lewis, The Everly Brothers, Roy Orbison, Carl Perkins, Johnny Cash, the Eagles, Gene Vincent, and Brenda Lee, not to mention ones such as the Byrds and Bob Dillon among others that played around with genre and created the Country Rock and Southern Rock genres, and pure folk singers who are much closer to Country in sound than R&B.
And, as I stated white gospel played a part because all those people were influenced by them, as evidenced by the fact that they specifically used Southern Gospel quartets such as the Jordonaires, The Blackwood Brothers, and the Stamps or members of those groups as their backup singers. Also, if Country played a role, as anyone knowledgeable about the history of R&R agrees they did, Southern Gospel played a role because Country and Southern Gospel are linked at the hip, just as R&B and Black Gospel is. The only real reason for a separation was that record companies segregated albums by race at the time. Secular Country and R&B, along with their sacred Gospel sisters are all kissing cousins that together, along with pop, produced R&R.
I am tired of race essentialists that cannot accept that one group or race didn’t fully invent something. Rock and Roll, like almost every cultural product of America, is the baby of many different mothers and fathers and mixing in the melting pot of the USA. Black and White, native and immigrant, Christian and Jewish, all had a hand in Rock And Roll.