People have their reasons for moving and people have their reasons for staying. Most reasons are usually connected to family. How does one pick up and leave elderly parents behind, who will care for them? How do you pick up and just leave your married kids and grandchildren? Or one spouse wants to and the other spouse doesn’t so it is a Shalom Bayis issue and the couple just isn’t on the same page.
Then there is the fear factor. You can’t control another person’s fear or anxiety no matter how much you try to reason or rationalize. Your bitachon says that Hashem will watch out for you and it is more dangerous riding a subway in NY than walking the streets of E”Y. That does not help someone else’s fear and anxiety. You have no idea how many New Yorkers have never even had the experience of visiting Israel for this very same reason.
Many, many people’s hearts are in Yerushalayim while their feet are firmly planted in NY. That is just how it is, and no one can judge them for it.