Well, yes and no.
According to the graphs below, the general direction of intelligence, while spiking across several genres over the last 10 years, has decreased overall.
Yes, I said third graders. Because only 2005 and 2006 would have given a reasonably competent third grader a tough time. Sure, we know hit music lyrics aren’t the peak of sophistication, but who knew the bar was this low? - Andrew Powell-Morse
There are a lot of reasons for this. Remember that I mentioned that word length plays a role? Well, Country is the only genre generally devoid of words like “oh” or “yeah” repeated 20 times in a row. Sorry everyone else, but if you say it in the song, it’s counted as a “lyric.”
But it’s also about the syllables. Country music is full of words like Hallelujah, cigarettes, hillbilly, and tacklebox. Add to that long place names like Cincinnati, Louisville, Mississippi, and Louisiana, and Country has a serious advantage over the competition. - Morse
As promised, Ke$ha does manage to score the worst of any major artist I looked more closely at. Not just a little worse either, although Lady Gaga makes a valiant effort to keep up (keep down?).
Unlike the other genres, the Pop stars who stand out are a bit less surprising with the gold, silver, and bronze going to Mariah Carey, Adele, and Justin Timberlake, respectively.
Pop actually holds its own pretty well with Mariah Carey scoring higher than anyone in the other three categories. Bravo Mariah, bravo!