Complex sentence: They became urbanized but found themselves at the lowest rung of the society, able to afford only the older, rundown housing, and often restricted to the lowest economic strata because of competition with other ethnic groups.
Split into simpler sentences: They became urbanized but found themselves at the lowest rung of the society. As the newest and poorest group, they could afford oly the older, rundown housing, and often were restricted to the lowest economic strata because of competition with other ethnic groups.