The extreme example would be the US. It received a huge amount of immigrant shortly often its funding and eventually prosper. The native got fucked though.
Oh and I must provide this example : anciant Egypt culturally absorbed many invaders despite losing to them. The only changes were the name of the dynasty. This proves that sometimes even a hostile invader can integrate itself in your culture.
Or it would skyrocket it.
Places with high immigration are places that are doing well. Places with low immigration are places in decline.
The extreme example would be the US. It received a huge amount of immigrant shortly often its funding and eventually prosper. The native got fucked though.
Oh and I must provide this example : anciant Egypt culturally absorbed many invaders despite losing to them. The only changes were the name of the dynasty. This proves that sometimes even a hostile invader can integrate itself in your culture.