The writing is juvenile, the band's attitude towards other music is insulting, every album sounds more or less the same, and there's an argument to be made that their fame partially stems largely from a Canadian law requiring Canadian music to make up a certain percentage of radio time. According to sources[0], their new album is getting outsold by Jason Isbell & The 400 Unit's new album, they're a fairly straight country act, so I'm not sure I'm even willing to take Nickelback's popularity as a given in 2017.
Like the other commenter said, Foo Fighters would have made a better example. Maybe Coldplay. Chili Peppers. Look, I understand that art is subjective, but at the end of the day, some art is less subjective than others. Nickelback deserves their spot in the pantheon of groups who get shit on whenever you mention them.
You have a rational access to music, and I respect that; though not everybody cares about an artist's street cred while listening to their music.
Indeed, country seems to take over the guitar torch, and why not. Coldplay mostly doesn't even have sounds that resemble a guitar anymore. Chili Peppers, yeah why not! I want guitars to somehow stay in the charts, or I'll feel quite obsolete with my hobby (electric guitar)..
I realize that you qualified your remark about Coldplay with "anymore", but it should be noted that their first two releases were guitar-centric and they were actually musically amazing (imo). I don't know about their more recent releases, although I believe they collaborated with The Chainsmokers for at least one of their latest songs. I'm not sure if this is representative of all their new songs, though.
CanCon, as the process is known, has many problems. It has forced radio stations to constantly play the Tragically Hip as well, who I would argue deserve to be played.
The melodies are a little too close to gain my respect. It's like they were tasked with making music for a Batman movie and started browsing the previous movie scores.
Green Day had their moment, although it has passed.
The Black Keys are good, but maybe not that mainstream.
The best show I've ever seen was Avenged Sevenfold, which is definitely in the metal niche. But I'll never forget when they had a break in the middle of the show, and their lead guitarist came out and just solo'd for a while. Incredible talent.
If you listen to the whole of their albums and not only the commercial hits, it's a really solid rock band.
Now give me some of the other examples of rock bands that regularly make it to the top 10.