You're making three assumptions: one, that there's still establishment (in my opinion, it'll be replaced by an unknowable hive mind), two, that its moral principles disapprove of creating parallel universes, physical or virtual, in order to subject their residents to one's personal amusement, three, that parallel universe travel is either unavailable or a controlled technology. Ultimately, the mega-computer would play a role of "big brother" that prevents everyone who's not "hooked up" from doing everything it disapproves of, but that would be a late stage of development. And it could limit its big brother functions to self-defense - for example, preventing non-hooked-up people from building nukes.I'm not sure about parallel earths and the like. If you mean physical time/multiverse travel, I cannot assume this to be possible. Parallel earths could be reconstructed virtually, but I doubt the establishment will allow you to subject billions of humanoid creatures for your personal amusement.
In any event, space exploration should be a viable path for those who do not wish to hook up.