It's driven primarily by ignorance and it muddies communication, especially over time. We should maintain some degree of pressure against such unnecessary change.
How much literature has disappeared from history because certain languages or vernaculars fell out of use?
Hell, why do we even bother teaching classical English if it's just going to change, right? We should just let kids learn from their parents and media - no use being a prescriptivist!
And yes, I do believe that some languages and dialects are vastly more expressive and unambiguous than others, but I don't expect the average person to understand that. Ultimately we're all free to speak as we wish but don't shame me for trying to preserve the necessary consistency that makes language useful.
> How much literature has disappeared from history because certain languages or vernaculars fell out of use?
The answer is not very much, comparatively. Most of the known losses of old works has been due to destruction, not communal loss of ability to decipher. Here's a summary of objects with unknown scripts:
(Just a joke, it was actually exponentially longer ago)
Sometimes that means correct people using a word incorrectly, because that might educate them about something they didn't know.
Sometimes though that means educating people about how languages evolve and that the ship has sailed for some expressions.