The problem is, as long as drivers demand range with electric vehicles, and energy storage is much less than liquid petroleum, the bottom of the vehicle is the only place that large, heavy pack arrangement can go. You make the tradeoff: How much armoring needs to take place to avoid the most common damage/failure scenarios.
I have no doubt Tesla is learning quickly from these events, and is plaining alternate or improved methods to armor the pack from road debris and damage.
The other thing to keep in mind is that the fuel tank is usually located in the rear of the vehicle while potential ignition sources (engine) is located in the front. This can reduce the risk of a fire as well. However, the exhaust system runs to the back of the car.
The battery itself is also segmented such that thermal runaway doesn't cause a cascade to the whole battery (which is why the driver here had ample time to continue driving and pull over).