rm..I don't know whether you are speaking of reality or not... The Demographics of the country disprove your thesis?
http://http://www.med.umich.edu/gcrc...demograph.html
Hispanics will become the largest ethnic(MINORIY GROUP) but they are still far from the largest group!
Obviously their impasct will be positive because as you indicate they are family oriented, hardworking, people who adhere to a tolerant but moral belief syystem.
The problem with all this is that Americans regardless of ehnicity or race are citizens who adhere to the nation of their choice. Their custioms gradually become shaped by the culture in which they reside and work!
Not so illegals who break the law to come over the border and work. They in the main don't expect to assimilate?