They have their own music label that helps handle music copyright & they have a different deal structure in place. V has 440+ licensed music, around 200+ is what we hear on the radio stations. Rockstar also likes to get more unknown, smaller artists to create music on some of the radio stations & these are much easier to pay fees for due to "exposure".
To my re-collection, none of V's music has been pulled since the launch in 2013 & I know at least 1-2 radio stations have been added in that time frame. I wouldn't worry about music in VI.