Because the author uses Berlin as an example. As a millenial that grew up in Berlin, I just think that the hype about, what used to be alternative, mainstream clubs is flattening. Especially techno and electro clubs. They are just not as great as social media wants you think they are.

People who love the music will go their for the music and will keep going. Social media folks that go there for the drugs and epic party will lose interest, because it's not as epic as they think it is.

Apart from that other alternative clubs are just doing fine (I am going mostly to drum and bass parties). Even though they got less. But I think the club dying there was because of other reasons, not the missing audience