Sanskrit in the Indian subcontinent has a long history, and not many are familiar with them. Lots of other scripts and languages in East Asia are relatively unknown (for example from Indonesia)
Even though people are not so familiar with classical Indian civilization, they were very highly literate and the extant corpus is enormous. It easily rivals or exceeds classical Greek and Latin. I have heard that the Mahabharata is 10 times longer than the Iliad/Odyssey.
On that line of thought, probably it’s Tibetan and buddhism that must have an extensive library. Most of these works have survived for a very long time.
Sanskrit is widely taught in younger years. Funding needs to go to bright PhD students to make the field again. It's extremely conservative and territorial after so many years of hardship.
The whole of modern linguistic theory, including the regular, context-free, and unrestricted grammars, were fully worked out in still-preserved Sanskrit.