Because there is no other way to export the oil except through the Sudan controlled oil pipeline, South Sudan's revenue is effectively controlled by Sudan.
Clearly this creates an incentive for opposition forces to first secure the oil fields as they are working to do and then strike a deal with Khartoum, before conceding control in any peace negotiations.
In the meantime, a hungry population and years of unmet expectations have put enormous pressure on South Sudan's first independent government to deliver so-called "peace dividends" and to deliver them fast.
These dividends are costly partly because South Sudan is a vast country with almost no tarred roads and few services. Of the handful of functioning schools, clinics and hospitals, the majority are run by South Sudan's humanitarian community, itself anxious to see the new government take-over.
Furthermore, fears of a demobilised military coming home to no jobs makes it imperative the government maintains its expensive security apparatus currently absorbing over a quarter of stated government expenditure.
Civil servant recruitment and salaries are on the rise and currently constitute more than half of government budget leaving little money for delivery.
If anything, the first two years of independence have only managed to convince South Sudan's leadership how difficult it is to meaningfully deliver services within any particular election cycle.
It is abundantly clear to even the casual observer that promising and delivering better services is an unlikely path to securing power simply because it is so difficult to meet the population's expectations in South Sudan.
Accordingly, the promise of a democratic system that grants power in return for service delivery appears hollow to many power brokers in South Sudan.
These dynamics shape the raw economics of decision making in South Sudan. When combined with low life expectancies, risks of continued internal and cross-border conflicts, a politics dominated by ethnicity and tribalism, worrying signs of baked in corruption and nepotism, a stark and dangerous incentive structure emerges.