An old advantage that the Church had back in the days before mass media and assimilation was the fact that immigrants and their descendants saw the Church as as bulwark of protection against the larger American society. These ethnic communities were also tightly knit, hostile to outsiders, and centered around the Church. In the short term, this brought considerable political influence to the Church, but, in the long term, caused the Church to be seen as an "ethnic social club" that one abandoned as they became assimilated and moved up the social ladder. Even amongst many in my own family, the Church is seen as a remnant of the days of the tenement/rowhouse and having limited expectations.
Problems extend beyond the aggressively secular bourgeois outlook of the descendants of (white) "ethnic Catholics." Aside from the Filipinos, many of the new immigrants are coming from cultures that lacked an indigenous clergy to foster devotion, or (in the case of urbanized Latin Americans) have seen the same secularist impulses, albeit at a lesser extent than her, in their own home countries. For the past few decades, the Church has centered their outreach on provision of social services to the immigrants, with little (or very poor execution of) catechises.
Clemenza:
I agree with your analysis, and the Vietnamese and Filipinos have done a better job fostering vocations than say the Hispanic immigrants. Again, the new Abp of Los Angeles, Gomez, is the kind of Bishop needed and is one types that I think will start to usher a reform and revitalized Catholicism, i.e. he continues an impressive group of Bishops being appointed by Pope Benedict and the ones appointed in the later half of Pope JPII’s papacy.