Why did the Russian immigrants come during the major periods of immigration?

Answer 1

Russia was one of the poorest nations in Europe. It was decades behind Western Europe and the U.S. in industrialization, so there were few factory jobs, and those were located in only a few places in that vast country. It was also slow to adopt modern agricultural techniques so farming was not as productive as it could have been, there were few railroads or even good roads to transport goods from one place to another, and their restrictions confining Jews to just certain provinces meant that there were too many merchants and craftspeople in those areas for most to make a decent living, while other areas in Russia would have benefited from more people with those skills. Russian peasants remained serfs - not quite as bad as slaves but not free either - until 1861, long after other countries had freed their serfs. The freed serfs received very little land from the government and had to pay for it over a period of several years, so they were very poor, and there was not enough land to support the growing population, so many former serfs or their children were forced off the land looking for work in the few factories. Unemployment was high and wages were low.