Back on topic though....
Here are my two cents on nu metal. The not so important anecdotal preface just for a little...context : I first knew of korn at a VERY young age in 1996.
Anyways...I would have to imagine, Korn's self titled album in 1994 turned a lot of heads. Whether they were actual metal heads, or people who were into 90's "alternative" bands who happened to be ok with heavier stuff.
Nothing really sounded like it...
As far as guitar tone, as far as being heavy without really playing metal. To be fair, yes, there were several "proto nu-metal" bands/releases on major labels who perhaps laid down the foundation for Korn getting signed to sony. Prong? Helmet?
People often mention faith no more and rage against the machine (two bands I don't really care much about), but I don't really see too many parallels beyond these bands having "new" and "different" sounds.
So I'm sure, a lot of people who saw Korn between 94-97 opening up for Ozzy, Danzig, Megadeath, Fear Factory, Sick of it all, uhhh, lots of other surprising bands, were probably like "wtf is this shit". But I'm sure there had to be just as many who were impressed. They were selling records before they were radio darlings. So yeah, korn was never a talented band, but they definitely had a dark and heavy sound that I'm sure did not fit into a perfect box at the time, that wasn't tailor made for the "nu-metal fanbase" because such a fanbase didn't exist!
Korn's sound by follow the leader stopped being dark, stopped being heavy, and well the Nu-metal box had been solidified. 99% of the 100's of Nu metal bands who were to form and get record deals were taking cues from Korn's most palatable elements.
My point is...being a style that likely always functioned as a "we're gonna make it big" sound, that never had an underground/diy incarnation/movement, never came from an organic scene other than what...a few clubs in LA, never ending up going in a non-commercial sounding direction. Like I wonder...what if Nu-Metal went in the OTHER direction? Now, people are going to say "well what about slipknot"..but I don't see them as a deviation at all. You had ross robinson applying his korn magic on a band with a pure money gimmick. Ok, some of the drumming can be wild...but I never saw slipknot as much heavier or much of an outlier.
FURTHERMORE, you have plenty of bands today who both consciously and subconsciously incorporate nu-metal elements into whatever style they're doing. The latter do it though because that's what they cut their teeth on and aren't even aware of the concept of nu metal. But it just sounds like nu-metally metalcore or nu-metally deathcore.
Like...there has never been an "extreme" nu-metal band! IMO anyone who understand what it would take to create one would have enough intelligence to go "but nu metal sucks" and not do it.
TLDR : wack music who cares