Just wanted to echo this. Everyone thinks the pop music that came out when they were younger is the good stuff and that the new stuff is terrible. This has always been the case.
To that end, my beef with a lot of modern music is it's totally low effort. I'm running on three hours of sleep so bear with me on this one, I may not explain it well, but, every modern pop singer sounds like they just got wheeled out of oral surgery, propped up in front of the microphone, and told they only got one take. Everyone sounds sleepy, mumbles, trips over words, sings off key and off beat even with heavy use of autotune and quantization. I imagine some of this is an intentional decision in order to make stuff sound more "real" and "authentic," especially with how digital all the backing music is, but it just sounds lame as hell. And between the constant flubs left in the final take, the general half-assedness of the performances, and the trend towards sparse and/or "experimental" instrumentation, every slick, glossy, high-budget pop record now sounds like an unfinished demo tape. (EDIT: Lady Gaga is a notable exception to this rule. Lady Gaga whips ass.)
YouTube doesn't work from my work computer, but two examples that stand out to me are "Work" by Rihanna and "Hold Up" by Beyoncé. "Work" is not only totally incomprehensible and suffering from a melody that doesn't really work with the music, but Drake's verse is frequently just completely off beat. It's not like, an interesting syncopation, he's just... off beat. "Hold Up" sounds like five or six different songs stitched together as a series of bedroom ideas and the fact that it was on a grammy winning album and took fourteen people to write is the most insane thing in the world to me.
Of course, most modern rock sucks too, but for different reasons.
I'm often subjected to modern pop music but it's of the hip hop variety. This type of "Hip Pop" has rappers who think they can sing. It's very bad and whiny and when they do rap, there's no balls or aggression. I'm not a fan of Hip Hop but if I have to listen to it, I'd rather hear some strength and power in the music. I realize that could be worthless criticism because maybe these "Hip Pop" guys aren't supposed to be angry.
Anyway as terrible as this stuff is, it doesn't sound like unfinished demos to me. Even if the rappers are bad singers, they don't sound off key or off beat to me. I think that Drake guy is one of the people my kids listen to. I don't know. Maybe since I'm always trying to tune that music out, I don't notice all the mistakes in it.