One wonders how obliging SE13's taxi drivers are, and what cars Mr Kail has in mind. Between 1994 and 1998 I lived mostly in London. I went to work on the Tube, but needed a car for social and other purposes at the weekend. In 1994 I bought a second-hand 1980s saloon for pounds 535.
During the following four and-a-half years it covered 45,000 miles at 35mpg. It cost pounds 120pa for insurance, pounds 350pa, on average, for repairs and servicing (with minor work being done at home), pounds 150pa in tax, pounds 70pa in breakdown insurance and pounds 75 to have it scrapped when it wore out. It broke down only four times.
It went all over the country, on all kinds of roads, at all times of day and night, often at short notice. Taking taxis to all the places that car went would not have saved a fortune.
Carlessness is probably acceptable for a bachelor leading a quiet, settled life with few out-of-London social contacts, or with a life that can be planned, in detail, a long time in advance. But it is not practicable for most of us, even if the car rests unused during the week.