Autonomy's role in trucks and buses cannot be ignored, either. Long-haul freight trucks, when operated autonomously, shouldn't need to stop other than for a malfunction or to recharge. Also, since a truck has much more space than a car, there's much more room for batteries, thereby extending the range. The result is the faster transportation of goods, which means reduced costs for retailers and manufacturers. That creates a demand for precisely the kind of truck Tesla's preparing to build.
That being said, Tesla is moving into this arena right at the same time as several other companies, so it's not without some very stiff competition. But at least Tesla's in on the ground floor this time, rather than playing catch-up as it is with passenger cars.