Yes, because MP3 playback is "too hard."
This is a response to backlash over the fact that the PS4 doesn't have basic media-playback capability. Not even CD playback, which is built into every cheap-as-dirt Chinese DVD drive!
The media player and UI on the PS3 are pathetic, but instead of fixing them with a simple user interface, Sony just DELETES the functionality altogether! Oh, but they had time to REQUIRE Facebook integration for user avatars and photos, instead of simply using the camera that COMES WITH the system.
As time goes on, it's clear that there aren't enough designers to do the work that's required.