Ports certainly are valuable. Ethiopia doesn't want to depend on the Eritrean ports. But it's a lot cheaper to pay taxes for Djibouti to maintain order in its port than for Ethiopia to create order in a Somali port. And to create order on the roads. Also, it's probably expensive to cross the Ogaden plateau. Which brings us to the Somali rebellion in Ogaden, which would surely escalate if Ethiopia annexed Somalia. Maybe if Ogaden gained independence, it could annex Somalia.

But mainly, it's Ethiopia's failure to claim the ports that makes me doubt their worth. I dispute Eliezer's claim that anyone would care. But some sense of propriety, perhaps Westphalian, prevents other countries from recognizing Somaliland.