It is amazing. No one benefits. A group may think they can avoid the ill effects by staying tight but their kids drift off. The biggest threat to any person who wants their child to follow their religion is not conversion to another faith, it is conversion to nothingness, to secularism.
Certainly not the Jews themselves whose practicing faithful are likewise marginalized, obliterated and ameliorated in the threshing machine of secularism destroying souls daily with the "saving graces of materialism".