Reread the last paragraph:
If it was caused by a lack of assimilation, there would be a stagnation, not a decline. The old country values of Hispanics are one's that are very socially conservative. Old school Catholic. The fact that this is occurring in the third generation is a sign that these old world values are being discarded in favor of the more "modern" American views.Since 1965, when then-Assistant Secretary of Labor Daniel Patrick Moynihan, a New Deal liberal, warned that the growing number of single mothers in urban areas was a ticking time bomb, the number of children born out of wedlock in the U.S. has more than doubled, with some of the sharpest increases among Hispanics. It’s no coincidence that their children and grand children are now paying the price. The consequences of the decline of traditional marriage are widespread indeed.
In short, your own source proves the exact opposite of what you are trying to prove. Assimilation is not always a good thing. Especially when the values of the country that is immigrated to have been on the decline for decades.
The difference in the outcomes between back in the day and now has nothing to do with a difference in willingness to assimilate between past immigrants and current immigrants, and has everything to do with how our own culture has changed over time.
In this particular case, we'd be better off if there was less assimilation occurring and a stronger desire to hold on to the values of the old country.