This is a pretty rose-colored way of putting it. Put another way: Somali society has a long and deep history of decentralized clan-based organization which, for better or worse, was deep-rooted enough that replacement with a centralized democratic government failed.
The system you describe didn't merely survive the failure of centralization, it was one of the existing Somali institutions that resisted centralization and won out in the end. Which depending on one's perspective on Somalia's current state could make it deeply problematic as a local maximum that makes the current status quo unassailable.