Ambition usually breaks down long before effort runs out. The failure point is structure. When the work is undefined, motivation gets spent on interpretation instead of execution.
The practical move is smaller and less glamorous than people expect. Reduce the plan until it exposes a sequence, not a mood. Name the constraints. Decide what a first visible win looks like. Once that exists, energy can attach to something real.
This is true for products, careers, and private projects. The system matters because attention is finite. Clear structure protects it.