The actors have ownership of the show. They hijack it.
The actors have a shared supertext. They are on the stage for much the same reason. This enables complicity between the actors.
The audience shares in forming the illusion. Suspension of disbelief is on their terms. The audience knows that we like that they know that it is only an illusion. We don't insult their intelligence. As Peter Brook said: Of course it is not real! This promotes complicity between the actors and the audience.