The metal scene is actually still mostly like that. Perhaps less so in America but there metal was basically killed by the hair-metal movement anyway and became extremely small ever since. Ignore the Nu-metal stuff - since mostly they are of the sausage-factory variety, but you did also have Slayer, Death and Manowar who wrote their own stuff, experimented with new ideas (Manowar basically invented the combination of choral and metal music), produce their own stuff, play their own instruments and push boundaries. Even metallica has had periods where they created real art and their the most commercial metal band America ever had (and the best-selling world-wide of all time).
This is a LOT bigger in Europe - the best metal for two generations have come out of the Slavic countries - Norway, Germany and Finnland in particular and the generation before it was Britain. Priest and Maiden were fantastic and Maiden is still fantastic, still touring, still innovative - they may have grown old but they never grew stale (I saw them live a few months ago and it was one of the best shows I've ever been at). The German scene started out with bands like Accept, which was a one-hit-wonder in the US but had a long and illustrious career back home, and moved into legends like Hammerfall and Blind Guardian. Later they and their neighbours would birth bands like Amon Amarth, Children of Bodom, Korpiklaani, Nightwish - all of which had their own unique approaches to a very wide genre which had already significantly innovated from other metal subgenres (a focus on singable lyrics, low-use of bass but heavy use of rhythm guitars, extremely rapid double-bass-drum patterns, elements of opera, choral and classicalmusic mixed). And most of them are unknown outside their home countries. Meanwhile Norway gave birth to black-metal which is one-part music one part polical protest against the dominance of the state-church, and then Armenian/German band Powerwolf took the stylistics of black metal, mixed it with the musical stylings of powermetal and based their lyrics on the mythology of the Holy Roman Empire for a completely unique sound and style.
There are still great bands out there pushing boundaries, combining absurdly different influences into truly unique music - they just aren't in the USA anymore. In many ways the country is just too conservative. Every time you have an artist actually pushing boundaries, trying different things, exploring a different approach to theatrics - there's a million protesters blaming them for every ill in society. In the 1980's they burned Maiden's records (though the band didn't mind because, in their words: 'before they could burn the record - they had to buy it first'), in the 1990s they blamed Manson for Columbine (even though neither of the shooters listened to the band), a few months ago buzzfeed blamed Slipknot for the racism of Trump supporters (so it's not just the rightwingers who do that), and a judge had to tell law enforcement that listening to Insane Clown Posse does not automatically make you a gangster (so it's not just metal bands either).
That's why it doesn't happen anymore - because in America any band that doesn't toe the line very carefully will never get airplay, never get on radio - just face a constant barrage of harassment and horror. So while bands and musicians may be brave - the record companies aren't, they will have one or two controversial acts (because controversy also sells) but they won't risk anything more.
Back in the mid-1990s Oasis was planning a tour in the US which was struggling to sell, Bon Jovi at the time said "Oasis will never be very successful here, because America is too conservative"
And that's coming from the least controversial, least metal, musician to ever play hair-metal about a band that, honestly, was just a fairly average British pop-rock band who did nothing particularly original or special memorable in their music and whose sole claim to notoriety was once outselling the Bible and calling themselves "Greater than god" - which they stole from the Beatles anyway.