Songwriting/Cowriting defines country music?

Obviously it doesn't, but everytime I see anything online about songwriting or co-writing, everyone mentions two things: country music and Nashville.

Nashville may be more country music than everything else, but it seems that everyone relates Nashville, and by extension songwriting, to country music. Since Nashville DOES have more music than just country coming out of it (Paramore, for example), where is an aspiring artist suppose to connect with a songwriter in the rock genre?

I'll almost be posting this in the Songwriting and Music Publishing Forum, please help with any thoughts on the subject!

RC~