What might take the place of late-generation European American ethnicity?

As Herbert J. Gans writes, ethnicity among fourth-, fifth- and later-generation descendants of European immigrants (LGEs) may be disappearing, and studies of LGEs should be undertaken along the lines that he proposes. LGE nostalgia for pasts that may never have existed and LGE intermarriage rates with non-whites as well as the ideology of multiculturalism, the easy availability of travel and communication, and the proliferation of dual citizenship might provide further contexts for such studies. In some cases, might the darkness of ethnicity precede a new dawn of transnational cultural and culinary practices, adopted from real or putative countries of origin?.