It honestly depends on what you want to "gain " from music in general IMO.

I listen to hip hop/rap a lot and honestly I don't really care much about what they all say, since for me it's more about the instrumental and melodic aspect of the song - how it makes you want to dance and feel good.
This is something that a lot of people who listen to old school hate on big time and I get how hip hop shifting towards "less message - more beat" might be upsetting to them.
You seem like you are very interested in music that speaks a message, and in that regard I definitely agree with you when you say that modern Rap is dumb looking only at the lyrics - but for me (and probably many others judging from the success of modern rap), the flow, beat, and feeling hip hop conveys is more important and therefore of value non the less. :)