I don’t think any of these bands created a “new genre” of music. These are all rock bands, RNR being a major genre of music contrasted with Jazz, Blues, etc. “Grunge” , “Hair Metal” are labels and labels can get kind of silly. The bands from Seattle had their own sound and each was a little different. It represented a change in the sound from what had been the popular rock sound during the 80s. Typically the next wave of rock music consumers coming want something different every 10 years or so. The popular sound gets stale, watered down and copied to a caricature of itself. It’s a reoccurring cycle in rock music. See Billy Joel’s song regarding Punk music, “It’s All Rock And Roll To Me”.
Solid post. There are a myriad of "styles" and the sheer number of labels can be dizzying - as can be any conversation that seeks to affix a label on any particular band.
I always like to refer to the Eagles in these conversations. What are they? In their vast catalog there are elements of blues, country, "southern rock", classic rock, etc.
"Hotel California" (the song) is actually a fandango - the chord progression being in what is commonly known as the "Spanish progression". There's actually a mariachi cover version of Hotel California, with Spanish lyrics, that is fabulous.