Just a few stray notes.
Everybody is proud of his country of birth.
All societies were matriarchal initially.Most natural.
When I look at the map, of countries to the west of India and those in East, I find Islam which is very much against the Mother concept.
Farther West, we have Christian countries of course originating in Palestine , close to Iraq, not that very different from our Mother concept. .
Historians have pointed out the great similarity of temple rituals from ancient Sumer (Iraq) and Dravidian South. Heimendorf , an anthroplogist has suggested that when Iran was at its peak of power ( some time around 700 BC, the assyrian empire was defeated by them and they settled down in far south of India. Very likely.
The Janapadha period ( around 700 BC ) in Gangeticplain was turbulent.
Panini taught in the border land University of Taxila ( Thaksha seelam) (Peshawar). OF PERSIAN EMPIRE
Paniniyam was the definitive grammar for Sanskrit.
Mother worship is prevalent in all states of India from far south to far east. under various names. Kali, Bagavathi, Bhavani, Gowri, Parvathi, Durga, .
I think it is only in India that the entire country is worshiped as Mother. .
So, Saaktham I would venture to say , is the most prevalent faith in India.
Beautiful personification of Divinity in Women as Valour, Wealth and Wisdom. ( DURGA, LAKSHMI AND SARASWATHI)
Second comes Vaishanavam of pastoral cattle-raising clans ..
Kashmeer was supposed to be the seat of most orthodox Saivism.
Ganapathyam was of Maharashtra region,
Koumaram of Tamil region. among the many.
It is quite possible that the entire country had these modes of religious worship.
Fire-worship only , belonged to Brahmins possibly a branch of Iranians , the other branch being Zorastrian.
Thus there is tremendous cultural unity throughout India. Political unity of India was achieved as early as Nanda empire ( before Chandraguptha Mourya! who converted to Jainism and fasted unto death at SravanaBelgola near Hassan. IN KARNATAKA
So, cultural and political unity was not anything new . It was always there .
Leaving out the far South of Tamilnad, the entire country even including parts of Afaganisthan were under unified govt. and administration. in Magadha times itself.
The Dhana Nanda was not a Kshathriya. and was least under the influence of Brahmanical Dharma Sastras.
It is possible that the entire intelligentsia spoke Sanskrit and common people , a colloquial version known as Prakrutham.( I am thankful to English that I could take part in this forum!)
Buddha preached in even less orthodox language 'Pali'.
Scholars in Pali can be found in Ceylon. and interestingly, Ceylon has never been considered part of India even in Ancient times.
In due course, regional dialects developed over a span of a few centuries and just as the Holy Roman Empire gave rise to modern European Languages and its nation states , here also regional dialects emerged. all owing their origin to Sanskrit in literary form and Prakrit in colloquial form.
This is a very recent phenomenon. ( around 1400 AD).It was the Vaishnava Bakthi movement that created theses literatures. PurandharaDasa, Gnanadeva, Nanak, Ramadasa, Thulasidasa, Chaithanya, Jayadeva, Meera Bai, Kabirdas. and many more.