Mond means that the society of Brave New World, where they live is too socially stable in their ways to birth any form of tragedy.
Explanation:
The society of Brave New World is extremely consumerist and self centered in that they are not even able to center themselves to see what is actually wrong in their society at large.
Unless this happens there is no way that a writer of Shakespeare's caliber could ever arrive to write a tragedy on the human condition or the society at large because there is no one to think about that.
Unless people introspect their condition there can never be a text like that.
