The difference between Kenya and Tanzania is the government and the people(human capital).
These Tanzanians have a proactive government that is efficient and less corrupt and that why most buildings are built by the government. On the other hand, Tanzania has a very week human capital and a weak private sector.
Meanwhile, Kenyan private sector is robust and active and almost all buildings are built by private institutions. Kenyans are being let down by their corrupt and inefficient government. The day we get a President like Kibaki only South Africa will dare compare themselves with us.