Why is America's financial district (s) all in New York as opposed to spread across U. S. States?

Like isn't the movie Trading Places set in Philadelphia, not New York? Isn't Los Angeles pretty much its own major capital city on status equivalence with New York City for fame and name recognition? Shrug? 😞😅
Why is America's financial district (s) all in New York as opposed to spread across U. S. States?
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