I was talking about AC/DC there, not the Velvet Underground.
You're imagining things I never said. Musically, the VU was an alternative to most/all other rock music of their time. I accept that. But how is it possible for them to be "widely" in line with a genre that is defined by its diversity? You can still use that argument to call all sorts of stuff alternative. The book you cited also mentioned Throbbing Gristle; is all industrial music now alternative?
According to most people, yes. I doubt that you're a listener of industrial music though so I accept your ignorance of that. Velvet Underground is clearly an early alternative rock group and they sound clearly as such.
I did not invent you stating that Burzum matches my description of alternative music.
So are you saying that Burzum, for example, did adhere to the mainstream conventions of rock music at the time? Because if not, it logically follows that he would be alternative by your definition. Same goes for Black Sabbath tbqh.
This totally ignores the second part of my statement. Get better at reading.