In the master service and parts there was mention of this topic. CD sales are on the decline so Mopar has stopped putting the players into the radio. The RA3 and RA4 have controls for an optional remote CD player.
Edit was to try to upload the radio comparison chart. Apparently a 432KB pdf is to big. If you would like a copy pleas send me an e-mail.
Sure there is - same result, too - one size does not fit all.
Much as iPod/MP3 players could jack in through an AUX jack, now folks with CDs can just get a portable CD player and jack THAT in. Provided, of course, they still MAKE portable CD players. I think I saw one in the dollar store the other day.