Living in EY is generally regarded as a mitzvah kiyumis. This means that there are legit reasons for remaining in Chu”l, and these can be taken into account when considering whether or not the fullfil the mitzvah kiyumis of living in EY. Once one lives here, making “yeridah” is more problematic, as it’s an action of removing the status of fulfilling the mitzvah.
Practically however, we are noheig to wear tsitsis every day, which is a mitzvah kiyumis.
Regarding gedolim living in ChuL, ask them why they haven’t moved. I have asked many gedolim in America this question, in a respectful manner. The general answer is that a leader cannot abandon their folllowers. While many rabbanim have chose to make aliyah, this is a tough decision to make because of these competing pressures. Ask your Rav, it’s a serious shayla. Most families in EY, especially those who try to work, can support their families. The answer as to whether or not one should remain in America when the only reason not to move is that it takes hard work… not pashut.