You rarely ever see the big rock or metal bands just plugging it out on stage nowadays. It's more about the acoustics, sound engineering, and melodious voices rather than rock-hard guitar, heavy percussion and raspy vocals. Why, though?
There's simple reasons, such as the fact that simply put, music styles evolve (or devolve, however you may want to see it). You had jazz in the 60's, heavy metal and hard rock the following 2 decades, grunge and nu metal throughout the 90's and 2000's. Then it phased to rap, pop, and EDM, where flow, melody, and beat drops became mainstream music.
It's not to say that there aren't other reasons. For example, the advent of spotify means that album sales and records mean less than what they used to 20 years ago. Spotify is free. Mostly, without the annoying ads asking you to purchase premium. Yes, I agree, someone needs to purge those out their programming. But still, vinyl costs a whole lot more than music streaming apps. Along with the aforementioned evolution of music, this plays a role as in why we don't see too many hard rock bands selling out stadiums anymore.
Then of course, there's the fact that the old blood just doesn't give way for new bands to grow to their heights. Instead, they keep raking in their money, selling out stadiums worldwide. Normally, new bands make their name by playing as a subsidy to the big bands - for example, how Breaking Benjamin made a name for themselves opening for System Of A Down, or Van Halen playing for Black Sabbath in '88. However, now it's a case of elitists sticking to what they know, because they're simply not fed any content from new bands. Why? No popularity, which is consequence of bands like Metallica and the Scorpions playing sold out shows even when they have literal grandchildren.
However, it has to be stated that they're not wrong. There's no uniqueness to rock anymore, other than one or two bleak exceptions. Bring Me The Horizon truly has embraced the market of an exception, offering something new with combining electronic synth elements used in rap and pop with grunge rock's heavy guitar patterns and Metallic screaming vocals by the one and only Ollie Sykes. Other than them though, barely anyone has scraped the surface of innovation; it's sad to say, but most new bands share carbon copy footprints with their previous gen counterparts.
There is hope though. There are bands like Bring Me The Horizon and Ghost which have successfully sold millions of albums worldwide, alongside the whole Rockstar complex of sold out shows and multi digit stream numbers. However, it's still to be seen if any music video released in latter years will break the 2-billion view mark on YouTube, only ever achieved by Guns N' Roses with their '91 hit, November Rain.
Can BMTH, Ghost and other bands live up to the Taylor Swift's and Ed Sheeran's of the world? It seems so; the resurgence and the grind of keeping the genre alive over the pop-rap years has been successful, and it seems we're on the precipice of the next big band breaking onto stage. Fingers crossed, it comes bloody soon.