Electric truck maker Rivian's $5 billion deal with Volkswagen Group nets Rivian some much-needed cash. But it also gives Volkswagen a path to a future in the auto industry it has struggled to gain on its own.In its short lifespan, Rivian has enjoyed praise from the automotive press, received chart-topping customer satisfaction ratings, gone through one of the biggest initial public offerings of all time, and watched its market value swell to$150 billion.But since then, Rivian's shares have plummeted. As of ...