No Somalia is not a sufficient example of anarchy, at least not to the extent that warlords are still in control. Also attempts to establish a new centralized government are ongoing there as well.
Warlords (as with any other dominant collective social formation) obviously destroy the prospects for a society free from such coercive power regardless as to weather it comes from well established modern states, or temporary semi feudal gangs. I think the confusion derives from the oversimplified and ideologically charged use of the word "anarchy" which means no rulers, not just a mere absence of a modern state.