The Last Scene : A Structural Question

So it dawned on me after making my wife sit through a three+ hour production of King Lear that, from a casual fan's perspective, the last scene of a Shakespearean tragedy must seem a huge bore.   Here's the pattern:

1. Almost everyone, including the hero, will die.  All deaths might occur onstage, but if they occur offstage, someone will surely come in to announce it. In some cases, such as the Lear I saw last night, the bodies will actually be dragged back onto the stage in case you missed it.
2. Someone will be left to explain what happened.
3. Someone will be the guy who just walked in and says, "What the heck happened here?"
4. Leftover person will now retell almost the entire play that we've just watched to new person, to catch him up.

Take Hamlet.  The only one left standing is Horatio, who tells the story to Fortinbras when he arrives.  Or Romeo and Juliet, where Friar Laurence is left to explain things to the Prince.  In Lear, Edgar and Edmund catch Burgundy up in a hurry (and if they'd spent a little less time doing so, they might have saved Cordelia!)  Othello doesn't totally fit the pattern, as Othello is still alive and learning the story himself when Cassio and Lodovico arrive.  But there is still that whole "tying up the loose ends" thing.

My question is, why?  Was this some sort of requirement of the audiences at the time, that they would only go home happy with the show if they felt that it was all neatly packaged up like that?  Why is it so important that the Prince learn the details of Romeo and Juliet's death, for example?  The audience knows.  Why not just end it right when they die?  All you really get after that is an announcement that Romeo's mother has died (offstage, of course, see rule#1), a promise of statues, and the prince's wrap up.  What was it about the fashion of the time that made Shakespeare end his tragedies this way, and not on the death of the hero?  It's the same with Hamlet - why is "And flights of angels sing thee sweetly to thy rest" not the last line of the play?  (Although for that I'm sure  there are Fortinbras fans who are ready to tear me a new one :))