Distortion of monophonic tones (single notes/voices) became accepted in the mainstream quite rapidly because the circuits used to produce it quickly improved, informed by feedback (no pun intended) from musicians.

Nobody hates ugly sounding distortion more than he or she who practices 5 hours a day with it.

Single note distortion, at its best, is a harmonically rich sound which shares something with bowed instruments and reed woodwinds.

Nasty sounding single distortion has not gained complete mainstream acceptance. Musicians who do that on purpose will remain niche, even today. From time to time, such nasty sounds make appearances in mainstream pop, but only as a kind of "cameo". The statement is, "we are inserting this ugly thing here specifically for its idiosyncratic effect, haha! But only a few seconds, we promise".

Distortion (other than perhaps mild distortion) has never been fully accepted in roles where the multiple voices of a complex harmony part would be distorted together.

Nowhere was that better seen than in jazz/rock fusion, which accepted ragingly distorted guitars for solo work, but not so much for the rest of the music: except, of course, in passages where the guitars provide the "sound of rock": distorted fourths and fifths and whatnot, or double stop bluesy cliches and whatnot.

The music best known for distortion and that couldn't exist without distortion (and a lot of it) is of course heavy metal, which is a big landscape of styles and sounds.

In metal, the harmonies from an individual guitar part tend to consist of only a few notes. The clean chord is transformed into something else, which perhaps cannot be described in music notation. Complexity comes from the distortion. Distortion includes the sum and difference products, which relate to the tonality and scale of the music in unsual ways. Those notes are not identified. If notation is used at all, the underlying clean notes are notated: e.g. C-F# tritone on the A and D strings, over open E bass. Heavy metal uses syncopated and alternating rhythms to separate bass notes from upper notes in three and four note chords. This is not only to create rhythmical excitement, but to better separate the notes.

The notes of a distorted chord are also easier to for the ear to identify if they are introduced separately as a lasciare suonare arpeggio; that's a thing in metal.

Harmonic textures are also created by combining distorted guitar parts. Using two lead guitars originated in rock, with groups like Wishbone Ash. Multitrack recording allows an unlimited number of parts to be layered.

As someone who is very much into heavily distorted guitar with long feedback loops, I appreciate your comment (especially for the insight). I'm a huge fan of doom/stoner/sludge/psychedelic metal (and all variations of those), where distortion and feedback are often used to create sounds that are difficult to notate. Combined with progressive metal/rock, which is heavily reliant on that jazz/rock fusion, and you get entire genres built around the harmonics and odd sounds that show up from lots of distortion.

I feel that Sunn O))) - named after the amplifiers, are a great example of slow rhythm music that relies upon heavy distortion and feedback to create the atmosphere and primary sound of their music. This is just a modern band, but the experimentation and techniques go back to psychedelic and acid rock from the 1960's, and mostly center around Black Sabbath as "the" band that really created the prototype for the sound.

Monolord, Bongzilla, Acid King, Bongripper, REZN, and SLEEP are some great modern examples that fit what you've described.

To sum this up a bit: Harmonic distortion is well accepted, unless done to an extreme amount. What people seem to struggle with most is intermodulation distortion, cross modulation, etc.

If you ever want to hear a guitar sound as rich as a synth, listen to someone running full polyphonic outputs for each string into a distortion per string. You get the rich harmonic violin/synth like tones of every string but can play full chords without any of the intermodulation products!

I'm kind of surprised guitars have stayed monophonic for as long as they have, and I feel like the next advance might be a cultural shift of guitars to a true polyphonic output path. Would definitely open up some interesting DSP pedal opportunities as a bonus.

The future is distorted guitars that can play complex chords imo

> Distortion (other than perhaps mild distortion) has never been fully accepted in roles where the multiple voices of a complex harmony part would be distorted together.

I'll fight this by agreeing with you. Saturation (a form of mild distortion) on the master is what I like to refer to as "the shit" because a nearly imperceptible amount really makes a track cohere. It takes a super light touch though, but I'd bet (without evidence) it's used on most tracks today.

I love the analysis but I think this ignores the percussive aspect of the electric guitar.

I am a huge thrash/death/black metal fan and a huge Ligeti/Reich/Ives/Ravel/Debussy fan so I could never call metal harmonically rich.

What to me makes metal is the percussive and melodic aspect combined of distorted, often palm muted for extra percussive effect, guitar strings in 5ths. Harmonically though, it is hard to get more simple.

It is kind of interesting how long it took for people to start applying distortion to other parts of the track outside the guitar. Seemed like that started when people were doing 4 track mixing on little cassette tascoms that would clip unlike expensive studio multitrack setups. Neutral Milk Hotel and such.