Adapting and reinventing in career and life is crucial as it enables individuals and organizations to keep pace with a changing world. The speaker illustrates this with an analogy of switching cars while racing down a highway, emphasizing the need to make quick transitions to avoid losing time. They highlight the pressure to maintain a certain pace in one's career and the danger of either the work getting stale or individuals getting tired. The speaker stresses the importance of constant reinvention to avoid collapse and to effectively adapt to the changing world.