> The city would be shrinking if it wasn’t for international immigrants, who don’t come to the city for the public transit, but rather the welfare system and ethnic social networks.
I think your numbers are wrong: the city's foreign born population has been stable for at least 15 years[1]. We're not even at historic highs; those were before WWI.
[1]: https://cmsny.org/publications/data-briefing-on-new-york-cit...
> the city's foreign born population has been stable for at least 15 years
This statement doesn't contradict the one about international immigrants keeping the city from shrinking. It is easy to imagine how immigrants come to NY, give birth to natural born Americans, who then move out of the city. This process can come to some kind of a dynamic equilibrium with a stable population of foreign born people.