Something glossed over by articles like this that discuss "Sanskrit" as a singular language is that prior to Panini, the spoken Vedic Sanskrit language was far less codified and rules-based, and replete with swashbuckling irregular grammatical and phonetic forms that were in free variation, and often used for rhythmic or poetic effect, just as in living spoken languages today. It was a campfire language, not a schola…
Was this the reason for slow death of Sanskrit as a living language? Too codified and "pure"? Hindi thrives precisely because its very happy to borrow words from anywhere and everywhere.
I doubt that most Hindi speakers today would easily grok the dialect spoken during the Delhi Sultanate
Sanskrit remains understandable after 4000 years