what happened to ths good old days when immigrants assimilated, got jobs and raised themselves up. Why are we now expected to lower our standards?
There are a lot of things at play.
First off, I'm not sure the Italians assimilated any faster than the Mexican are. But Italy was across an ocean, so the immigrant couldn't play the game of "one foot in, one foot out" that the Mexicans play. They couldn't wire their wages back home. And we were a much more sane nation back then, we didn't start putting up street signs in Italian and printing ballots or other documents to suit the immigrant. There also was no dream of Italian conquest of the America. Mexicans hold this vision of conquering at least the Southwest on behalf of Mexico - why assimilate when the plan is conquest?
All in all, this is a VERY different situation than the USA has experience in the past.