Someone should wait for acceptable available content before spending on a TV set that can display that definition. As for TV programs broadcasted in 8K, I doubt that it will ever be a reality because of the increased costs.
How many 3D films or programs were shown by a TV channel? IMO, 8K definition is only good for screens of over 100 inch. Since the majority of TV owners can't afford screens that big, I doubt that the format will live long.