LCDs screens on those SMS phones are much bigger. Phones are design for us to communicate. The obvious reason why LCD screens have appeared in hp are for us to dial up a telephone number plus SMS. Even a Motorola "Brick Phone" has a LED display for us to look at.
iPod shuffle is small and lightweighted that it is design for people on the move. Why bother with LCD screens when iPod Shuffle is already so small. Besides it consumes your battery life too.
Mac design things which not only looks good but also cater for busy people like us. They design it so that we do not need to open our eyes and keep looking at the songs that is going to be played.
Half of the time when I use to listen to my Walkman and MDs, I just let it run thru. Really could not be bothered about looking at the LCDs screen.