I wonder if iTunes works differently from my iPhone. In iTunes, when I view a playlist, I am given a Shuffle All option. On my iPhone, when I view a playlist, I am (also) given a Shuffle All option.
I know when I use that option on my iPhone and I am listening in my car, I see an ascending indicator on the display: 1/259, 2/259, 3/259, etc., etc. etc. I have made the assumption that the software randomizes the playlist, and then plays the entire thing in that random order. So, eventually, I do hear each song in the playlist exactly once. At least, I’m pretty sure that’s what happened when my current playlist actually made it to the “end” recently.
Interestingly, sometimes I want exactly what you do not: a true random play experience. I may not mind at all a favorite song being played twice in a row, or twice in a short time period, and true random would enable me to skip a song that I might not want to hear at the moment, but know that it has a chance to resurface before the “end” of the playlist. In fact, true random would never have an end.
I’m thinking that you’re treating “random” and “shuffle” as equivalent. I don’t think it is. In doing a quick Google search, I find several articles that suggest “shuffle” does exactly as I thought, and that there is no true “random” function. Here’s one: http://lifehacker.com/5929611/why-itunes-shuffle-isnt-random-and-how-to-fix-it.
What might be interesting to discover is what users expect from “random” and “shuffle” and how those expectations match what Apple actually does. And then, would users be delighted or confused if Apple provided both “random” and “shuffle” functions. Clearly, this would be an interesting content experience exercise.
Finally, the geek in me is curious to know what happens at the “end” of a shuffled playlist. Does iTunes just restart from the beginning with the list in the order that it shuffled it in initially, or does it reshuffle to provide a different experience the next time through?