Boxed sets

Back in the early 80s when I started playing D&D and other RPGs, it was very common for companies to produce boxed sets, especially for the initial product in a game line.  The classic Mentzer Red Box D&D set is a great example of that period.  For the AD&D line, there were a bunch of boxed sets in the 90s, but those were mostly for campaign settings (Ravenloft, Planescape, Dark Sun, etc.).  Then the boxed set went out of style.  The hardback rulebook returned as king.  But now, in the last few years since around 2008-2009 boxed sets are back.  D&D Essentials, Doctor Who, Dragon Age, Warhammer Fantasy and more.  So are they back for nostalgia reasons?  Are they back for design reasons - combining the rules, dice, adventure all in one box?  Are they back because of marketing, a choice to have the boxes on store shelves like "regular games" instead of books?  I'm guessing it's a combination of these.  In any event I'm glad to see them although to be fair I can't say I've really seen them much in the big box stores yet, not counting the big book chains.