Even if everything goes according to plan and Somalia is on an upward trajectory, the issues of the past will still haunt our capital. Most if not all public infrastructure development is currently focused on the capital region because of its volatility, indirectly leading the nation back to centralization which will not be acceptable to the regional states committee.
Likewise sending the capital to Hargesia, Kismayo, or Garowe will give certain clan enclaves special privileges. The region of Banaadir and its beneficiaries will not agree to such a concession. It is political suicide and a major dent to their bottom-line which is understandable, even if the majority of Somalis would benefit moving on from Xamar.
Since neither side of the aisle has the military might to overrule the other's ambition - Which is little compared to the Kenya/AU or Ethiopian military means anyways - Dividing the branches of power and allocating it to different parts of the country seems to be the only political solution that everyone COULD possibly agree on. It also follows the federalism theme we have been harping on since the turn of this decade.