And other whispery singers that get more props for being a pretty face that can hold a note vs actual front stage singer capabilities. I think its odd the same listeners that would go ham on Brandy and MJB are willing to be lullabied to boredom by boring background vocals.
LynyrdSkynyrd perhaps had influence on Nirvana, as Jim Morrison, Bowie etc and based on the Nirvana sounds like a headlining rock band and not a coverband or filler band.

Don’t get me wrong, they have their place but it is, generic light subtle background vocals.