Polarization of the orientations occurs even in cultures where the life support systems are ample, so that all living members of the intelligent species survive. Polarization of the orientations occurs due to myriad decisions the entity makes, that build upon each other until the trend is undeniable. For those leaning toward the Service-to-Self, each self-focused decision requires that they harden themselves against others, and focus on what they consider the rewards for having done so. This tends to harden them, increasingly, as these decisions are made, until cruelty becomes a power trip, all sense of empathy having been lost. For those leaning toward Service-to-Others, each rescue of another is rewarded by the comfort and joy that another experiences, which is likewise experienced vicariously. Sacrifice is weighted in this light, so that as empathy and the ability to experience comfort vicariously increases, the sacrifice diminishes in proportion.
On worlds where there is no contest that can be termed survival of the fittest, this polarization still emerges and in approximately the same time frame. Death may not be the outcome, but maiming or torment is just as terrible. Survival of the fittest is not a scheme in God's plan, but a factor of life. Life adjusts, continually, to what surrounds it. Those genetics that incline the life toward successful living give it an advantage over life with less advantageous genetics. This is not a battle of genetics, but an action of genetics, just as tides are not a battle against the mainland but an action of the surrounding gravitational pulls. Most life is utterly unaware that survival of the fittest is going on, and the pace is so demure that one would have to live many generations to even see the trend. War, and the desire to kill the enemy is not genetic so much as it is a factor of control and greed, characteristics of those in the Service- to-Self.