> I think, and it is just my speculation, that for most of Indian History, Sanskrit was the link language.

> Just like "Latin" in the USA and Europe of the early 17th and 18th centuries, when all academic instructions were carried out in Latin!

You're suggesting that Sanskrit became a scholarly language, which no one was disputing. You're even using as a metaphor Latin, which started out as a vulgate tongue - which is the argument you are doubting.

Edit: It also applies to your English comparison. English IS spoken by millions, just not by the people you are referring to. Are you actually claiming English isn't a mother tongue to anyone?