I think its naive to think hierarchies are obsolete. They have a function and reason to exist and this is not going away at all. Those at the centre, with power and resources will continue to use hierarchical structures because they are very efficient and fit for purpose. As routine work is automated certainly less and less of us will probably work in structured routine roles within large hierarchies. It think its more precise to suggest that both will co-exist and context is everything - IE compliance and conformance is important in a top down hierarchical model - the outer edge which is more bottom up requires different skills and attitudes. I think its more a matter of context rather than a binary either or situation.