Well, you probably won't hear it on the radio, but you'll see it pretty much everywhere else. I remember that after watching 8 mile; I was paying attention to the credits and after every song; they mentioned the artist, writer, and composer.
I'm not talking about the money here. This is an over simplified example, but let's say I just started listening to music and heard Vanilla Ice's "Ice Ice Baby" and I just loved the melody of that song without really liking the lyrics. So I go out and buy Vanilla Ice's Cd's hoping to listen to more of the same. David Bowie doesn't get the credit, but some prick like Vanilla Ice does.
("Ice Ice Baby" is a hip hop song written by American rapper Vanilla Ice and DJ Earthquake. The song samples the bassline of "Under Pressure" by Queen and David Bowie, who did not initially receive songwriting credit or royalties until after it had become a hit.)
http://en.wikipedia.org/wiki/Ice_Ice_Baby
Is it really a problem? No. In the end; the credit will be given. But keep in mind that this is the song that made Vanilla Ice famous and it could very well be because of Bowie's bass line instead of Ice's brilliance. Could it be considered intellectual theft; I personally think it could.