Both the Tigris and the Euphrates form in Kurdistan, and receive no other tributaries of note once outside the Kurdish mountains. The question of control over its water resources should be of great worry to any government in Baghdad, and loss of its Kurdish territories would be most dearly felt because of water, not oil. The entire Iraqi state has had a tormented modern history due mainly to the Kurdish question, and all parties would breathe in relief once a disassociation had taken place. Like Syria, Iraq too would become almost totally Arabic speaking, but less wealthy, and much less secure. To include all Kurdistan and all Kurds within such a country would unrealistically anticipate the brake up of many established state boundaries.
Contemporary world contains many sovereign countries that share a common language and culture.
There are, e.g., a score of Arab countries, a dozen Spanish-speaking, many who speak German or English, and three sovereign states with Persian being their official language. Many Arabic, Spanish, German, English and Persian speaking groups who live as minorities in other sovereign countries. A Kurdish state need not contain all Kurds or even most of the Kurds. Republics of Azerbaijan, Armenia and Laos contain only a minority of the Azeris, Armenians and Laotians alive today. Kurdish leaders like Barzani, Talabani or Ocalan may, realistically, legitimately and morally aim their aspirations at only their own respective portions of Kurdistan.