So music really HAS gotten shittier since I was in high school.
But seriously, using the "Billboard Hot 100" is pretty unscientific, that list says more about mass media than it does about musical styles. For example in the early 90s there was a lot of independent radio stations fueling that boom that were gobbled up a few years later. MTV was also huge and was getting pretty weird with 120 Minutes and Yo MTV Raps. The music being produced hadn't necessarily changed but more people were suddenly hearing it.
And now because of how schizophrenic everything is, the Hot 100 is a list of names most people have heard of but nobody actually listens to: http://www.billboard.com/charts/hot-100 Okay maybe not NOBODY, but since radio airplay is a key consideration that list has all kinds of problems.
In 1991, around one of their "revolutions" the ADAT was released[0]: "While synchronization had been available in earlier machines, ADAT machines were the first to do so with sample-accurate timing - which in effect allowed a studio owner to purchase a 24-track tape machine eight tracks at a time. This capability and its comparatively low cost, originally introduced at $3995, were largely responsible for the rise of project studios in the 1990s"
Technological revolutions that have lowered the costs of recording and distribution have often precipitated changes in the music itself. Not to mention the new capabilities introduced by new technologies like electric guitars, magnetic tape recording, sampling, digital recording, and whatever that robot-death-sounding thing that they keep doing in Dubstep is :)
It isn't clear to me that technology would have affected anything that they would have picked up:
"Harmonic topics, of which there were eight, captured classes of chord change, or their absence (eg, “dominant 7th-chord changes” and “major chords without changes”). Timbral topics, of which there were also eight, were things like “drums, aggressive, percussive” and “female voice, melodic, vocal”."
I also immediately mentally leaped to "electronic" music, but it doesn't seem to me that they were looking for that sort of thing.
Look at what blew up in the early 90's: grunge and rap, they were cheaper forms of the 80's rock and R&B that came before them. Rap probably wouldn't have happened without the 808 and samplers, and wikipedia puts the first affordable sampler at 1986 which fits the graph in the article pretty well.
I'm not saying it's all technology but when something is cheap and new that's an attractive combination for musicians looking for a different sound. And that new thing will have new strengths and deficiencies which will determine what types of music sound good on it.
But seriously, using the "Billboard Hot 100" is pretty unscientific, that list says more about mass media than it does about musical styles. For example in the early 90s there was a lot of independent radio stations fueling that boom that were gobbled up a few years later. MTV was also huge and was getting pretty weird with 120 Minutes and Yo MTV Raps. The music being produced hadn't necessarily changed but more people were suddenly hearing it.
And now because of how schizophrenic everything is, the Hot 100 is a list of names most people have heard of but nobody actually listens to: http://www.billboard.com/charts/hot-100 Okay maybe not NOBODY, but since radio airplay is a key consideration that list has all kinds of problems.