Here's why the title is often used:
* Vast Output: Shakespeare wrote a massive amount of plays, sonnets, and poems. He is considered the most prolific writer in the English language.
* Enduring Legacy: His works continue to be performed and studied around the world centuries after his death.
* Universal Themes: Shakespeare's plays explore universal themes like love, loss, ambition, and betrayal, making them relevant to audiences across time and culture.
So while he didn't hold any official title of "all," the phrase is a way to acknowledge his lasting impact on literature and culture.