You're assuming that private cars are the current dominant form of transport. That's not always the case.
Transport planners i've come across would probably start wittering about modal shift. If introducing more taxis into a city leads to a modal shift from taxis to cars, it's a good thing. But if it leads to a modal shift from buses to taxis, it's a bad thing.
A Machiavellian transport engineer might even consider restricting taxis so as to maximise the available modal shift to buses (or rail etc), to make projects to introduce those easier to sell.
Transport planners i've come across would probably start wittering about modal shift. If introducing more taxis into a city leads to a modal shift from taxis to cars, it's a good thing. But if it leads to a modal shift from buses to taxis, it's a bad thing.
A Machiavellian transport engineer might even consider restricting taxis so as to maximise the available modal shift to buses (or rail etc), to make projects to introduce those easier to sell.