So how's India different than North America?

I recently read this path-breaking landmark judgment rendered by the Indian Supreme Court (SC) on an appeal case that involved hearing on a matter of alleged injustice committed against an Adivasi individual, wherein the SC took a dramatically insightful look into the origin of Indian people itself.  Simply put, the SC basically declared that India, much like North America is today, should be regarded as a "land of immigrants".  The archives of The Hindu newspaper contain (non-case specific) extracts from the judgment (and a link to the full original text as well), check out http://www.thehindu.com/opinion/op-ed/article1081343.ece

Contrary to widely-held views of India being an ancient home-grown civilization that grew by and large "from within", this SC judgment propounds a new paradigm wherein one would begin to believe that India is also essentially a country of "external settlers" who upon their ancient immigration to India basically obliterated the original native aborgine inhabitants in due course of time, in a fashion perhaps not too dissimilar to how, say, Australia evolved as a nation.  While most of us are atleast partly familiar with this theory in the sense that the "Aryans" were regarded as the outsiders who colonized the "Dravidian" orginal inhabitants, the SC judgment elevates the older theory to a new level, wherein even the so-called Dravidians should be technically considered foreigners, leaving only the Adivasis as the original unadulterated native inhabitants of the land.

Firstly, you want to tip your hat to the SC judges who pronounced this judgment for the sheer depth of knowledge and courage of wisdom they chose to display in this case, that could well have far-reaching implications on how the identity and origin of all Indians is understood going forward.  If a historian or an archaeologist had made such pronouncements the nay-sayers would have readily poked fun and marginalized the theory, but who other than the SC to wake up our ordinary minds to a new dawn of possibility that we had hitherto thought improbable? After reading the judgment, which reads like a lesson that could find its way into our kids' history textbooks, I do have one question - Should we then conclude that North America today, at least in terms of the diversity of immigrant populus that constitutes its society, is more or less similar to what India was, say, some 2,500 years ago? So is there essentially no evolutionary difference between North American and Indian societies other than their age? Food for thought.