1. It’s the writing system evolving rather than the language. I think in the case of the Indic scripts this could be considered intentional as the scripts were designed to be practical in the first place.
2. Designers need to be active but defer to the native users. Just because designers can help bring all the details and quirks of handwriting into type doesn’t mean users want to abandon the limits of their typographic traditions, which might be practical if not so beautiful.
I think it can make sense in display types that will be used at sizes where a wide space sticks out, especially lighter sans serifs. I find the results in book fonts generally solve no problems and cause weird collisions like “for you” becoming “foryou” that interrupt reading. I've even seen this in some great types, used by great designers, in their own books. Nobody has ever complained when don't kern to space, but I've had complaints when I did. So my rule is to only kern to space if I'm sure it's and egregious flaw otherwise.