It's because it has been an autonomous region longer than Puntland and Somaliland
They have an excessive amount of natural resources and oil which would have a great impact on their economy.
Plus, it had an influx of immigrants and refugees coming to the autonomous region after the overthrow of Saddam Hussein as well as other issues nearby the autonomous region So, this must had a positive impact on their development
Another thing to note is there is diversity so they won't be an enforcement of one particular culture or language over the other.