Sure. The main issue with that is the unknown unknowns. In hypothetical cars an order of magnitude safer than today, we're talking about events so rare that a single (hypothetical) accident which kills all 7 passengers due to the Tesla misinterpreting an obscure Hungarian road sign meaning "bridge out ahead" will significantly influence your safety statistics.

There are enough youtube videos with people falling asleep in Tesla on the highway and a Tesla switching lanes and almost causing a frontal crash. These are known problems.

Maybe a billion miles are needed for a fatal crash, but for small mistakes it's much less.