Why did people leave Russia?
People have been migrating since times immemorial, leaving countries, moving into them, going across them. Major movements out of Russia have been a few: In the Czarist times, and Stalin times, newly conquered territories like Kazakhstan offered new opportunities. So people went there. Same with the Baltics. But this was intra-empire movement. Out of Russia but not out of the Empire. People who are not ethnically Russian such as the Jews or the Ethnic Germans had laws passed against them and they left- in large batches in the mid 19 the century and beginning of the 20th century. Also, at the end of the latter. During Soviet times many intellectuals, dissidents and artists escaped looking for creative freedom in the West. White Russians ( not the color but political affiliation) left when the White Army was defeated after the revolution of 1917. However, percentage-wise, very few ethnic Russians have left their country because 1) they love it 2) they do not have the money 3) their laws
Different people, different times, different reasons. My ancestors left because they were persecuted for their religious beliefs. People were being imprisoned, killed, property stolen, beaten, raped. You´d probably leave too. Many people left for reasons to do with lack of freedom, and poverty + a promise of a better life elsewhere is a huge reason why people emigrate.