Here's why:
* Shakespeare's Era: Shakespeare wrote and performed his plays in the late 16th and early 17th centuries. The proscenium arch style of theater, with its distinct stage and audience separation, didn't become popular until the late 17th century.
* The Globe Theatre: Shakespeare's primary stage was the Globe Theatre, which was an open-air, three-sided structure with a platform stage and a "heaven" and "hell" area above and below the stage. This design allowed for a more intimate connection between actors and the audience, with no clear separation between the two.
* Immersive Performance: The Globe's design fostered an immersive experience, with the audience surrounding the stage. The actors interacted directly with the audience, often addressing them directly. This kind of direct engagement was not possible in a proscenium arch theater.
While Shakespeare might have adapted his plays for a proscenium stage, his plays were originally conceived and performed in a much more open and interactive environment.