The number of medallions (ie, jobs) is controlled, which means their owners reap those profits, not the drivers, who must compete with each other for access to those medallions. Uber's breaking of the monopoly expanded the market and created more jobs.
The other difference is that taxi drivers have generally stable work. A guy can drive a cab consistently for years. The pay is not good, but the economics have to work out.
There's no stability, the cost for leasing a medallion was constantly increasing, as was the number of people with licenses to drive (competitors).
Cab companies and owners have enough wherewithal to make long term decisions, moreover, the 'drivers' - the ones on the end of the chain - if they are not owners - are not responsible for the fixed costs of the cars etc..
Where do you think the money comes from? Not being responsible just means they don't get to make choices - they're forced to accept whatever the car owner says.
Finally, cab companies are by nature, small - and don't have hyper-leverage over drivers. Cab companies have to compete efficiently for talent among their drivers. If you can call it talent.
Then why was medallion ownership the single best investment in the last 30 years? Compete for talent? Where?
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This article from the NYTimes is rather informative, and being from 1995, it's not a submarine for Uber et all: http://www.nytimes.com/1995/04/09/nyregion/driving-a-taxi-di...