Ari > “a terrible shedding of observant Jewry in the United States” – What does this mean?
It means that those who came to US in the first half of 20th century had minimal rabbinic guidance and were assimilating. RJBS (and his father) were one of the earlies yeshivish gedolim who came to US before WW2. One of the famous earlier rabbis was walking around NY boardwalks protesting hillul shabbat and everything else. This was not attracting followers. RJBS calls these people “checking each others’ tzitzis”.