The little jump from the car chassis to the ground is nothing compared to the distance the bolt has to travel to get down to the car in the first place.
Cars get hit all the time. In most cases there is no or little damage. It's the safest place to be in a thunder storm nevertheless. Unless it's a convertible.
The cage structure of the car keeps the current flowing on the outside of the car, it cannot enter into the passenger compartment because of physics. It's called a Faraday's cage.