The United States and Canada lured large numbers of immigrants from Europe with offers of incredibly inexpensive land. Consequently, most of our immigrant ancestors made their fortunes as successful farmers. Even if they had other professions, people of the 18th and 19th centuries always aspired to be farmers, which was widely regarded as the most noble profession and even as a source of moral virtue.
As our ancestor's families outgrew the available land to farm, they repeatedly migrated west into new territories, where they could acquire more inexpensive land. For example, over a period of 300 years, the Simpsons migrated constantly in search of new land, progressing through Scotland, Ireland, Delaware, Ohio, Iowa, Nebraska and, at last, Saskatchewan.
Below is a chart the occupations of 5 generations of Kate's and my family. Almost all began as farmers, even much of the family of my New York mother-in-law at the bottom, although they were the first to become urbanites. We would have to go back another 2 generations to see farmers among their number.
The last to leave the farm were my Hungarian-Canadian grandparents, who were part of a very prosperous farming community around Kipling, Saskatchewan. They originally had other professions in Hungary, such as bootmaking, but, in Canada, they were exceedingly prosperous as farmers. However, within a single generation, almost all of their families also left the farm for the city.