I agree with you that grandchildren of immigrants usually do not retain the language and values of their immigrant grandparents if that language and those values are different from other people in the nation in which they live. As to religion, it seems to me that that aspect of culture is more likely to be retained than are language & values.

However, even if they don't speak their immigrant grandparents' language, and don't retain their grandparents' values and religion, these grandchildren of immigrants may still retain some forms of their heritage that give them group pride and self-esteem.

Witness the huge Caribana Caribbean festival that has occured in Toronto for 40 years. This is evidence tht people of Caribbean descent in Canada {and those people of Caribbean descent who attend that festival} identify themselves as being of Caribbean descent {at least some of the time} and are interested in retaining & celebrating facets of their cultures.

Of course, a cultural festival is not the same as immigrants or descendants of immigrants changing the basic governmental structure of their host nation or being involved in those already existing governmental structures through voting, running for office, and other political activities.

That is a whole different story, the first part of which I would not support, and the second part of which I would very much support.