In a 2003 study by the RAND Corporation, economist James P. Smith finds that successive generations of Latino men have experienced significant improvements in wages and education relative to native Anglos. According to Smith, "the reason is simple: each successive generation has been able to close the schooling gap with native whites which then has been translated into generational progress in incomes. Each new Latino generation not only has had higher incomes than their forefathers, but their economic status converged toward the white men with whom they competed."Granted, at least in the passage above, Smith is looking at a particular time period (immigrants arriving between 1895-99, along with their kids and grandkids) that's different from the present day in several respects. Notably, there was a decent supply of stable and good-paying manufacturing jobs back then—three-fourths of Ford workers in the 1910s, for instance, were immigrants (mostly Eastern European, granted, but I assume Latinos could find similar sorts of jobs)—which can explain why the immigrant families of old could do so well so quickly.
A comprehensive 2002 survey of Latinos in the United States by the Pew Hispanic Center and Kaiser Family Foundation provides additional evidence of advancement across generations, particularly in terms of English proficiency. Spanish is the primary language among 72% of first-generation Latinos, but this figure falls to 7% among second-generation Latinos and zero among Latinos who are third generation and higher.Basically, Latino immigrants and their descendents do very well, especially when one considers that many are exploited and underpaid by their employers, and that they live in a country where economic mobility—not to mention public education—is nothing to brag about. I'd also suggest that maybe if the United States had decided over the past fifty years to help Latin America develop, rather than, you know, fuelling wars, installing various dictatorships, and conducting neoliberal "experiments" on countries like Mexico, then perhaps the Latino immigrants who came here would be healthier, wealthier, and better-educated and would have "assimilated" more easily. Fun to imagine.