If pop music is simply defined as "music that is popular" then I agree to a degree with the idea that pop music sucks.
That said, Rush has had a hit, Yes have had hits, Frank Zappa had a hit (albeit with Valley Girl), Stevie Wonder is a hit monster, etc.
"Rap has the same drumbeat repeated thousands of times"
This is just a silly statement. There are rap songs with excellent musicians (The Roots, for one) that don't just repeat the same drumbeat.
So you can't really make generalizations, and to do so shows ignorance.
I dig the guy who comments saying "This is why I listen to Zappa...."