Of course in the last several years, critical discussions are always talking about who sold out in the rap game?
In other generes that have been around as long or longer than rap have already reached at least 1 renaissance.
1. In the 60s and 70s, reggae was about culture also known as "the roots of reggae". Around the mid 80s the roots era has been overtaken by dancehall for the next 10+ years. Critics called the dancehall followers the sellouts who received airplay. Then in the mid-late 90s roots has reached a renaissance as new artists emerged. Roots artists that had their careers in the shadows of dancehall blew up such as Beres Hammond.
2. Around the same time is when Heavy Metal was a sub genre of rock. Ask some 70s rock fans what they think about Kiss, even though they topped the charts. Alternative Rock soon ended the heavy metal era while being heavy influenced by the earlier rock after the beatles....who also were considered sellouts in the 60s because of their use of drums.
3. Jazz in the 70's also expanded everyones concept of what jazz is with the use of electric instruments and integration of R&B. Herbie Hancock wasnt admired by all critics...especially when he made Head Hunters. Miles Davis was labeled a sellout after making classic albums, then made Bitches Brew using different younger musicians, electrical instruments, etc. But today its still considered a classic album. Years later in jazz the blues type jazz influenced by the early 20th century musicians prevailed again.
This cycle type theory is not that new of an idea, but looking at where hip-hop is and seeing the path that other genres of music took, it gives a perspective and "hope" for others.