And I can tell you that the state that I have lived in for early 70 years has been completely invaded from people from other areas. It is uncommon to meet others who were actually born here when we go to the grocery store or other places where we come into contact with the public.
Cultures change and the young people who should have the most concern have typically have no apparent recognition that it is even happening. The 19th century might as well be the 17th century as far as most are concerned.
You are intentionally omitting that “Russians and Ukrainians share a common heritage that dates back to the medieval state of Kievan Rus’ (862-1242). This state, centered in present-day Kyiv (Ukraine's capital), is considered the birthplace of both nations.” “ Ukrainian and Russian share about 62% of their vocabulary.”
France, Italy, Spain, and Portugal also share a common heritage and share much the same vocabulary. They are, however, distinct cultures and languages. Ukraine and Russia two separate nations derived from a common source.