@tempestt0st I think there's the obvious answer, that digital distribution has flattened everything, so you get a lot more music and fewer big hits, a lot of bands get popular in a niche. I don't know if figures for this sort of thing are available, but I suspect that singles in the top 40 represent a smaller share of the total market than they did.
Aside from that, Rick Beato had some interesting commentary on this: he ascribes this to a few factors, one being that overproduction (e.g., beat quantization, autotuning, etc.) makes all of the music sound uniform, and another that studios have been taking this extremely conservative approach where instead of signing a large number of bands and investing in them, studios have the songs written by the same people that wrote the hit songs in the 90s and have been consistently writing music that sells. So there's less innovation because every studio hires the same handful of people, and then wants those people to write something that sounds like whatever thing sold last year, and then they wash all the color out of the recording process.