Sergey Brin came to the U.S. with his family at the age of six from the USSR.[1] His family was probably admitted to the U.S. due to the religious persecution they faced: "Michael Brin [his father] claims Communist Party heads barred Jews from upper professional ranks by denying them entry to universities, and that Jews were excluded from the physics departments in particular."[2]

So his story is not very relevant to the discussion of H1-B visas and tech worker shortages.

[1] https://en.wikipedia.org/wiki/Sergey_Brin

[2] https://en.wikipedia.org/wiki/Sergey_Brin#Childhood_in_the_S...