I am quite a Nirvana fan but I just think this is totally absurd.

Nirvana's impact on the actual sound of music I would say is really not that much.

It is really Sonic Youth that had a much bigger impact on the 90s sound than anyone. Including taking Nirvana on tour as an opener when they were complete nobodies.

Even punk music barely felt the influence of Nirvana. I think you are confusing sound with MTV marketing.

It is actually curious how much Nirvana and The Beatles are not reflected sound wise in modern music.

Nothing close to say the way Bone Thugs-N-Harmony has influenced modern rap.