Favoritism in country music?

it really confuses me the way singers like taylor swift, carrie underwood, jason aldean, keith urban, and in the past, singers like shania twain and hank williams jr, get and have gotten so much love and credit, and yet there's singers like tammy rogers, david ball, rick trevino, & rhett akins, whom no matter how touching any of their songs are or no matter how country they sound, have never really gotten the credit they deserve. also why are so many country singers popular only for a certain amount of time? example: clint black, from 1989-1999 was one of the best-selling country singers. however, in the past decade, he's released some really touching singles, like "spend my time" and "the strong one" which unfortunatly never got the success they should have. mindy mccready, same story, popular in the late 90s, but 8-year hiatus with the hell she's been through, then releases an inspirational comeback single, titled "I"m Still Here"....does money play a role in this or something?