Dedicated "all business class" airlines have come and gone, irrespective of fuel costs or economic constraints.
It's a flawed concept because travellers paying premium fare have an expectation of flying in
separate class. When the entire cabin is just one class, there is no separation; all the seats are the same size, everyone is treated equal. There is no stimulus, nor "reward," for having forked out the extra cash to be visually separated from "cattle" class.
Furthermore, because of the large number of all business class seats in the wide body cabin, there are fewer cabin attendants per passenger than in conventional, much smaller, First/Business classes. Consequently, individual service and customer attention is less focused.
