I don't believe the vast majority of taxi drivers own their vehicles because in most jurisdictions the cars are tied to a taxi medallion number and those are much more expensive. I.e. before Uber taxi medallions in NYC cost on the order of two to three hundred thousand dollars because of limited supply. More often than not, taxi cab owners have more than one medallion/car and rent those out to drivers. This was a great investment pre-ride sharing

Even in NYC, some drivers would own their medallions - many of them banked on being able to sell them when they retire.