Hip hop is the most challenging art to be good at...thats why...

its the most lyrically challenging music...

and as for rock bands making music (instrumentals), making beats is very similiar.

its much harder art to deliver the lyrics, and much harder art to make the lyrics flow...

rock bands, etc...don't have to do half the work of hip hop artists (who make their own beats) -

not only do rock bands not write half the ammount of lyrics per song that a hip hop head does, they usually have others in the group that help write...where as hip hop songs usually rest solely on the one artist.

the lyrics in good hip hop are also more deep, more challenging to write, etc...

maybe we have so many shitty artists because the style they are attempting is so difficult.

dont get me wrong...im not saying hip hop is so great that no other art is worth listening to...thats not the case...i love to listen to other styles every so often....and i respect all other styles of music...but i'd rather listen to good, quality hip hop than any other.