“Consider the one who first sets out to climb a high mountain: does the plan he draws up while seated at its foot carry him all the way to the summit?”
Sometimes a single event shatters all the plans of a person's life, and he takes that blow to be the very center of his existence. But are futures built upon the plans a person makes? They are not.
Chapter 3 of 35 — 4 parts, 6 min in total.
Every faction in the Mahabharata plans meticulously. Shakuni plans for decades. Duryodhana plans the house of lac. The Pandavas plan their exile, their return, their alliances. Almost none of it survives contact with events.
Krishna's position is not fatalism. He plans constantly himself — the embassy to Hastinapur, the strategy at Kurukshetra. The distinction he draws is between acting with full care and then holding the result loosely, versus needing the plan to succeed in order to be at peace.