Philosopher, we don’t have much precedent to determine that, because up until the 1920s the majority of klal yisroel were frum.
It’s probably due to a lack of resources that in the early days of American jewry, there wasn’t a massive kiruv movement. The chazon ish encouraged kiruv in eretz yisroel, and even instructed yungerleit who were fit for the job to remove their yarmulkahs in kibutzim, knowing that people would listen to them more if they didn’t look too frum.
To think that we should abandon the millions of secular jews to be lost forever is not something I’ve seen advocated by anyone