The Gita’s most quoted teaching is also its most misread. It does not counsel indifference to outcomes. It counsels the separation of duty from the anxiety of reward.
A common misunderstanding turns nishkama karma — action without craving for its fruit — into passivity, or into a licence for detachment from consequence. That reading is hard to sustain against the text, whose entire occasion is a man being urged to act.
The more careful reading is about the location of motivation. If an action is powered by its expected reward, then the action becomes hostage to the reward: it degrades when the reward is delayed, distorts when the reward can be obtained more cheaply, and collapses when the reward fails to arrive. Whereas an action powered by the recognition that it is right survives all three.
This is not mysticism. It is the difference between a doctor who treats patients well because the outcomes are measured and a doctor who treats patients well. Both may perform identically for years. They diverge precisely when the measurement stops looking.