Having worked in IT for 27 years, I concluded some years ago that the new IFE systems have become way too complicated for the environment in which they operate.
They are sold by enthusiastic salesmen to the enthusiastic marketing people of the carrier. Each marketing team think that they will steal a lead on the competition by having more stuff, more easily available and more sexy. When nothing works, it isn't very sexy.
I can see the attraction (to the marketing kiddies) of having 'something for everyone' with games and all the rest but the technology is just not yet ready to deliver with 99% reliability. Another five years maybe. So, I still take my own music and reading material with me.