We do also do that too.
Every car is built with a fancy headrests and seatbelts and airbags -- the entire car is literally a helmet, and we require this on every new vehicle sold for decades. (And we require the seatbelt be worn too, legally enforceable by law in most areas)
We even check every single car sold to make sure the Helmet-worthiness of it is safe for the general public (see https://www.nhtsa.gov/vehicle/2019/CHEVROLET/VOLT/5%252520HB... as an example of a vehicle results)
When an occupant of the car is small enough such that the built-in helmet-worthiness of the car might be rendered insufficient, we also require they get extra helmet-like protections wrapped around their head/neck/body - see https://www.dmv.com/car-seats for specifics -- and even these are also legally enforceable by law in most areas