The only difference between the wideawake actors in this marvelous movie and those who cling to their ‘roles’ (making them very effective, skilled performers, of course,) is this: Wideawake actors have grokked the impossibility of any particular person acting – or awakening. Un-awakened actors haven’t, yet.
Does it matter?
To whom could it matter?
The movie mirage goes on in any event: just-so, just-this, nothing special.