Sometimes I think people on the west coast seem to think of a city as a place that's supposed to stay the same forever ("forever" being defined as starting at about 1960).
The lower east side was a German neighborhood, then a Jewish, Italian and Ukrainian. Dutch before that, of course. Then the Italians moved to Little Italy. It mostly became a Hispanic neighborhood. The Ukrainians mostly moved away and the Jews mostly moved away. The north of the neighborhood sort of became Japanese and Chinatown sort of started encroaching on the south and Little Italy slowly declined. Artists and then eventually giant condos started moving in. As you walk around you can still see marks left behind by the groups that departed many decades ago. For example, a few buildings still have prominent German inscriptions on the front, from Little Germany's high point in the 1880s – the Germans were gone by around 1900. You have no doubt whatsoever that your turn there is temporary. A city is a place of constant change. You are every bit a part of that constant change. But the city will slowly move on without you.
Don't expect anything to last longer than 10 years.