Wouldn't it have made more sense to name William Shakespeare's The Tragedy of Julius Caeser, The Tragedy of Marcus Brutus instead?

The title of the play as The Tragedy of Marcus
Brutus would make sense if one reads the play outside its historical
context.  Critics, scholars, and readers often debate the question of who the
protagonist of the play actually is.  Even though the play is named after Julius Caesar,
the development of the story and its characterization do not suggest that Caesar is the
play's protagonist.  Brutus goes through major internal conflicts throughout the play,
and thus seems more suitable to be named the protagonist of the
play.

But the play is a re-vision of the actual conspiracy
against Julius Caesar and an allusion to England's own fear at the time about the
successor to the throne.  So the play has to keep the title The Tragedy of
Julius Caesar to maintain the parameters of the
allusion.