Just to expand on that, Istanbul isn't even a state (though it's a very large and important city). The USA is a federation of states, with a multifaceted legal framework and also the biggest single-country economy in the world (EU is bigger, but isn't as tightly connected or managed).

Would the comparison of Istanbul to New York City be more appropriate?

I used the term 'states' too loosely, it seems. Specifically, I was in Baltimore, Washington DC, St. Louis, Chicago, NYC, Burlington, VT, and Madison, IN, on that particular visit. I hope this satisfies the detractors that feel I was speaking too generally of 'the states'. I was optimally able to get to and from most cities by bus, train, and airplane. However, in none of those cities was I able to optimally find a taxi (meaning, right when I needed it). Notable exceptions included NYC (from Penn Station, but not to it) and DC (though that doesn't really count, because I drunkenly boarded a taxi waiting for someone else when leaving the Capital lounge).

Usually, I would have to call a cab or use Uber. That's fine, but it seems different from the "just need a car when I need a car" observation that invited my quip.