[AareyBaba]

In the last two decades we have genetic data that paints a much more complex picture. India is a fertile land and people have been streaming in (and out) for at least 50,000 years. If people move just 30km away every generation that is enough to populate the entire land in a thousand years.

Also the existence of an isolated Dravidian language in what is now Pakistan is puzzling https://en.wikipedia.org/wiki/Brahui_language