I believe the Kiruv professionals and Kiruv Yeshivas should put a greater emphasis on outreach towards Modern Orthodox Jews, who are much more likely these days to be receptive than completely secular Jews. The secular Jews from the 1960s and 1970s are much further away today from any semblance of Yiddishkeit than back then. It is far harder, and much less successful, to reach them nowadays than back then.
Even though many MOs will not be receptive, indeed perhaps a majority even would not, there’s still enough of a minority, whatever the numbers may be, to work with. Much like in previous decades perhaps only 1 in 8 or 1 in 10 secular Jews approached by people doing Kiruv were responsive, that 1 in whatever the percent is, is a jumping board towards making Jews more observant.