I think part of this is a deliberate measure to make it harder for modern cars to be used as weapons (of course, there are other more prominent factors like fue

I think part of this is a deliberate measure to make it harder for modern cars to be used as weapons (of course, there are other more prominent factors like fuel efficiency and safety in accidents). With crumple zones and crash sensors, vehicles are often rendered inert in the event of a collision, and I think this is intentional; compare that with the Nice truck (which was obviously much larger than a car) that barreled through 80 people. It's basically the opposite of what you would want in a military vehicle.