Did Romeo and Juliet have to die for the story to be effective?

Shakespeare's Romeo and Juliet is a tragedy. If you were attending the theater in the 16th century when the play first appeared you would have seen a black flag at the top of the theater indicating that today's performance was a tragedy. Even in the opening words of the play, the Prologue, Shakespeare notifies the audience that the play will not end well. He does a major spoiler alert in this fourteen line sonnet as he speaks of Romeo and Juliet's love and that their parents feud would ultimately lead to their suicides. Shakespeare's tragedies almost always end in the deaths of at least some of the major characters and suicide is often employed to bring about that demise. Thus, Shakespeare uses suicide (and other forms of death, most notably sword wounds) to bring about the tragic elements of the play.

The story would certainly not be effective as a tragedy if the two title characters were to survive. It would really not be a tragedy if, for instance, Romeo had not taken the poison before Juliet awakened and he discovered that she was still really alive. At that point, he might have carried through with Friar Laurence's original plan and taken Juliet away to Mantua and lived happily ever after. While it's certainly an interesting idea, Shakespeare's tragedies just didn't do that. He may, however, have left one of the characters to survive. The audience would probably decide that the character was a tragic figure because they were deprived of their true love.

The only way that Romeo and Juliet would be effective had the title characters lived was if Shakespeare had made it a comedy. It could have ended at the end of Act II with the marriage of Romeo and Juliet (Shakespeare's comedies usually ended with a wedding—think of The Taming of the Shrew, As You Like It and Love's Labour's Lost). There is plenty of humor in the beginning acts, including the Nurse's banter, Lord Capulet's doddering exchange with his old cousin in the beginning of Act I, Scene 5, the bawdy conversation between Romeo and Mercutio in Act II, Scene 4 as well as Mercutio's treatment of the Nurse at the end of that scene. The problems would be with the feud itself, Tybalt's anger, Mercutio's dark side, and the foreshadowing of doom which runs throughout these first two acts. Shakespeare would definitely have had to alter these sections, maybe eliminating the feud and Tybalt, while making Mercutio a more light-hearted character and not quite so edgy. In the final analysis, however, it's probably best that Shakespeare killed off his two lovers at the end of the play. Otherwise, we probably wouldn't even be discussing the entire issue.