To native Southern Californians like myself, however, who grew up around a lot of Mexican-Americans way back in the 1960s, this doesn't seem like such a sure thing.
Or, a close friend of mine from elementary school was the son of a Central American banker who married a lady from Iceland. Another close friend had a Spanish surname too, although his dad dropped out of Yale on December 8, 1941 to enlist in the Army, so he wasn't Hispanic in anything except the Spanish surname. (The family claimed they were descended from an admiral in the Spanish Armada who was shipwrecked in Ireland in 1588.)
On the other hand, there were plenty of working class and poor Mexicans in Southern California in the 1960 who did not marry out of their cultures. Their numerous children and grandchildren have not, on the whole, set the world on fire.
The lack of high-achieving Hispanics in Southern California in 2013 is startling when you start to look for them. The current mayor is Mexican, but he's a mediocrity who took four tries to pass the bar exam. The leading candidate to replace him, the dapper Rhodes Scholar Eric Garcetti, claims to be Mexican on the grounds that an Italian ancestor got kicked out of Mexico during the Revolution one hundred years ago.
In general, what you see in California today is that while the rich are even richer than ever, there is less of the broad middle class prosperity that made California a global cultural leader in the postwar era. (Yes, I realize that non-diverse white bread Republican suburbs like Orange County couldn't, by definition, possibly have produced anything vibrant: except, they did.)
My observations have been systematically verified by a major social science project affiliated with the UCLA Chicano Studies department. The 2008 book Generations of Exclusion: Mexican Americans, Assimilation, and Race by UCLA sociologist Vilma Ortiz and Princeton sociologist Edward Telles documents a 35-year-long study of, first, a sizable 1965 sample of Mexican-Americans in Los Angeles and San Antonio, followed by a 2000 study of the 1965 sample's children, plus questions about the 2000 sample's children.
Our data also allowed us to investigate the educational achievement of the grandchildren of the original respondents, enabling us to distinguish a fifth generation-since-immigration. ... Figure 5.3 shows that these grandchildren of the original respondents, who are third to fifth generation, seemed to be doing no better than their parents. By this time, the third, fourth, and fifth generation were performing equally, with no significant differences among them. In the third generation, 85 percent had graduated from high school, versus 84 of the fourth generation and 81 percent of the fifth generation. ...
Many have assumed that the educational inequalities are attributable to the disadvantages of poor immigrant households, but the data here show that schooling outcomes stubbornly continue at low rates even into the fourth or fifth generation. The statistics presented thus far show that the education progress of Mexican Americans does not improve over the generations. At best, given the statistical margin of error, our data show no improvement in education over the generation-since-immigration and in some cases even suggest a decline.
Here are some graphs from the book. The first demonstrates the structure of their complex study. The "Original Respondents" column represented Mexican-Americans surveyed in 1965. Back then, among the first generation (immigrants) only 30% had graduated from high school. In 1965, the children of immigrants from Mexico had a 48% rate of high school graduation, and the grandchildren a 57% rate. But, when Ortiz and Telles interviewed the children of the 1965 respondents in 2000, they found stagnation, instead. In 2000, the fourth generation Mexican-Americans in their sample of the children of their original respondents had less education than the second and third generations. And the third column shows the same stagnation for the grandchildren of the original respondents, some of whom are fifth generation Americans.
The college graduation rates makes Mexican-American lack of progress starker:
And here's a graph in Generations of Exclusion from p. 110 using a different source of data but giving similar results. These are restricted to American-born third generation or higher citizens:
These findings obviously have major implications for Rector and Richwine's estimate of the fiscal effects of the Gang of Eight's amnesty bill.