JMO music has gone straight down hill since about 1980. That is around when computers started making a lot of music instead of musicians. Also it became more marketing driven than talent driven. A couple generations have grown up not knowing what they don't know.
You have had people make similar arguments for generations.
Before the Boy Bands and girl bands in the 90s you had the similar formula to many motown groups. They were the boy bands and girl bands before the later girl and boy bands. They all followed a similar style.
In the 80s' and 90's you had many hair metal or rock bands having the labels make them do a Power Ballad because at the very least that would put the band in the main stream and sell.
Back in the 50's the record companies did all they could do to get the records played on the radio...to the point of Payola being a thing.
Back in the day Disco was the electronic music years before today's electronic music. Disco was such a huge movement (even if just for a short time) that even KISS made a Disco song...I was made for loving you. Kiss was also one of the earlier bands that had a ballad in beth.
MTV also changed things. Heck they were so image driven that you had Milli Vanilli become huge stars. If it was only the music that was important they would not have got to good looking young guys to lip sync to other peoples music.
Every Generation when they get older thinks that most of the music sucks. That the current generation's music is not as important. That it is not original.
Heck even when Rap was coming out for the first many years you had all kind of people saying that the artists did not play their own instruments. Run DMC said all you needed was two turn tables and a microphone.
Even country music has changed a good deal. It went from country, to rockabilly to pop now.
Music is always changing and the older each generation gets they pine for what they liked growing up and complain about the new music not being as talented.
Heck fans of older rap even complain about newer artists being mumble rappers with little to know skill for lyrical content.