Aristotle points to six elements of tragedy in his momentous work The Poetics. These six pillars have become the basis of all theatre through the ages:
4) Diction (speech)
Can these apply to things other than theatre? A professional football game certainly has character, spectacle, melody (the National Anthem, music played between game), thought (yes, I know this sounds shocking, but there is strategy behind the play calling at least), and diction (the quarterback calling plays, officials calling penalties). While it is not scripted, does a series of events strung together not constitute a plot?
What about a political debate? It has diction, spectacle, thought, and character for sure. Perhaps a little weaker on melody, perhaps, and the same question applies about what actually constitutes a plot.
Something to think about at least.
Do these elements still apply today? How do they apply to non-theatrical events? If you remove a single element (especially plot), does the piece suddenly loose its theatricality?
If you were to come up with 5-7 essential elements of theatre, what would they be?