Most of what the article is complaining about is because the economics has led to monopolization.
At least back in the 1960s and 1970s, you had some individuality which would poke up. A department store wanted different clothes from the other department store to draw you in. A radio DJ wanted different music to get you to listen to their channel. etc.
However, once everything is a monopoly, there is no need to spend any money to be unique since there is nowhere different for anybody to switch to.
But popular music itself is to a high degree very same. That's not to say that there is no original music anymore. There is a big amount. It's just people tastes that decide what becomes popular, and everybody wants to hear the same.
And yet, fashion and taste change. It's just a matter of time.
What becomes popular seems to be whatever we get brainwashed with, ie what we get advertised.
It seems to be less driven by social changes than it is driven by profit motive of those able to feed most of us 10-15 minutes of advertising within each of the several hours of media consumption most of us partake of each day.
According to him, it is not just tastes, it is the way musicians get paid:
"Streaming platforms pay artists each time a track gets listened to. And a “listen” is classified as 30 seconds or more of playback. To maximise their pay, savvy artists are releasing albums featuring a high number of short tracks."
When films first became a thing, no one knew how to make them. The proven template didn’t exist. There was more variety because there was more experimentation, and eventually what was once pioneering experimentation becomes mainstream commodity and the novelty wears off.
The same thing happened with music when the synthesizer was invented; no one knew how to make music with a synthesizer so it was all experimentation. It still happens today in burgeoning subgenres of electronic music. A new sound is invented (or rediscovered, more recently), music producers flock to this exciting new frontier, eventually it reaches mainstream, and by that time it is no longer novel or interesting. Rinse and repeat.