That's not entirely true. There are places in Z1-2 where people live in flatshares etc. on ordinary salaries. I lived in an ex-council flat near the Elephant with three other people for a few years, for example.
That doesn't change the substance of your point, though. Very few people living in Z1 or Z2 run a car unless they're rich: parking is extremely difficult and public transport is so good that there are very few reasons to want one unless you're regularly leaving London.
That doesn't change the substance of your point, though. Very few people living in Z1 or Z2 run a car unless they're rich: parking is extremely difficult and public transport is so good that there are very few reasons to want one unless you're regularly leaving London.