It's not calls per person(they aren't calling a person). It's calls per phone - there's only about 3 billion cell phones in the world, so the number is over 8
with over 3 billion cell phones, that works out to about 8 or 9 spam calls per year to the average phone. Wile I do get these, it isn't a big deal to ignore them and move on with my life.
No. Batteries are expensive, and many people would just replace the car rather then replace the batteries. A battery that lasts a million miles and possibly a couple of decades would be well received. Right now it's just a concept. Until it actually gets built and tested we really won't know what it will cost to manufacture or if it will last as long as expected.