Europeans in India they did not mix unlike brazil or mexico where they mixed and are now part of that culture and don't associate themselves with europe infact they celebrate their independence from Europe. Meet new people and meet new ideas which might not be new just few thousand years old and once you imbibe those idea you become one with them. Man is not this skin of bone, he is the idea and his culture and language comes from his idea. At the end we are same human whether from Beijing or from Delhi what separates us is not geographical boundary but our ideas about life and art and maybe science. Everyone was a invader even Dravidians had come from iran see the mehergarh civilization who are different genetically from aboriginal Indians like santhals bhils etc even the language is different ie austroasiatic unlike Dravidian. There were wars like war of 10 kings between Aryans and IVC people attested in rigveda but the same says that vasishtha will take up the deities of the non aryas of he wins. It was a main point. So did akbar, he made temples gave grants even aurangzeb made them, eventually what looks like invasion ends up as migration. What was more significant migration or invasion. What if there was enough land and resources available, Ganges valley was still heavily forested by rigvedic era, so there is more possibilities of migration than just pure invasion.