The attacks in Brooklyn, Highland Park, Lakewood and Belgium bely this. Not to mention the high cost of a frum lifestyle – especially in the US. Not to mention cultural assimilation and outright intermarrriage. Both Rav Soloveichik and Rav Moshe say that aliya is a least a mitzva kiumit and Rav Ovadia says that it is an absolute obligation – and sharply criticizes those who do not do so.
I do not know who this person is or what exactly Rav Yaakov said to himThe Gra is quoted in Kol HaTor as saying that in the time just before Mashiach the chet hameraglim will attack the guardans of Tora with blinders. This was also stated by Rav Eliahu Guttmacher in a letter printed at the beginning of Em haBanim Semeicha and Rav Chaim Eliezer Vax in Nefesh Chaya at the end of Responsa 1 (see Torat Eretz Yisrael by Rav David Samson pg.249-250 footnote 29).