A question popped in my head while playing Saints Row the Third

A question that had previously come to me when I was playing GTA4 on 360. 
 
First, a little backstory: I originally played GTA3 and the others prior to GTA4 on PS2, but I purchased them for XBox as well so my brother could play them. While playing the XBox version of GTA3, I was able to tune to a station while driving s vehicle that would play whatever music I had on my XBox, I thought that was really cool. Cut forward however many years it was, playing GTA4 on 360, that is no longer possible, if I want to play music that is on my 360, (while not as extensive as on my original XBox, is still a decent amount,) it plays over the game audio and is not linked to a radio station in the game, same goes for SR3. 
 
Don't get me wrong, SR3 has an outstanding soundtrack, I especially love the Adult Swim station and the "mix tape" ability, but sometimes I would like to listen to some of the songs that are on my 360 in game and not have the game audio drowned out.  Now for the question:
 
If they could do it on the original XBox, why do they not do that on the 360? 
 
An acquaintance of mine said that they spend so much on the liscencing of the music thaat they probably want to make sure you hear it, and while that might be somewhat true, if that was the only reason, they wouldn't give you the ability to turn off the music. Any thoughts?