>>It clears out the old to make way for the new.

Just imagine working for a boss who had been climbing the company ladder 200 years. Or trying to buy a house in a market where people had been accumulating capital for centuries. And lest we think it's just the the economic system, look at the average age of politicians. Or science, the researchers who hold the most prestige are likely past the point of embracing new ideas. Any advantage which can be accumulated over time would be held almost exclusively by the oldest, and the world would stagnate.

Death is the natural law which requires every generation to pass the torch. Without it, there'd be no life for the young.