The issues with road deaths in the US has precious little to do with safety features of automobiles and whether they are extra or not (the fact many are mandated seems to be overlooked) and all to do with the woeful standard of driving, driven by a complete lack of meaningful driver training and total lack of enforcement of standards which would make roads safer.
The same can’t be said for the aviation industry, which treats safety as a priority, based on the amount of training required and the enforcement of standards associated with that.