akuperma,
early sephardim were coming here, running away for religious freedom from Spanish/catholic countries.
19th-20th century immigrants were also coming for more freedom. You can listen to tapes of interviews on Ellis Island website. Some say that the immigration officers asked about professions and directed them to the corresponding guild or trade union. Another Jewish lady describes how her family was saving money in Poland trying to send her to school, and here there was a free public high school … this is not to deny problems with shabbat and observance in general… was it the right idea for rabbis to advocate against going to Amerika except in some cases? Given the midrash that Yaakov sent Yehudah to establish yeshiva in Mitzrayim, maybe there should have been more strong rabinim coming early on? this is, of course, monday morning quarterbacking.
