Yichus is such a funny thing . Those who know that they were related to various great rabbis are so impressed by themselves for having it as if it has anything to do with who they are . It might, but not necessarily. I suppose I sound envious but not really. I might have some unbelievable yichus to some great rabbi but pogroms etc has made it difficult for me to keep track of my lineage. Most Jews have this issue. I have always thought that by virtue of being Jewish I have good yichus. I think that those of us who still know that we are Jewish know this because we have family members who stuck by tradition / therefore are good yichus. Since Jews lived only in certain enclaves it stands to reason that most of us if we do not descend from converts likely are related to those with the enviable yichus.