It's one of those things about which I have strong [goats.com] feelings [goats.com].
Anyone who attempts to generate random numbers by deterministic means is, of course, living in a state of sin. -- John von Neumann

i think both statements are correct. When looking at temporary communication (ie interpersonal, unrecorded) it is fine to have a changing language.
however, if you want to see written word, a changing language is ultimately detrimental. See the difficulty in reading ancient hebrew by anyone who knows modern hebrew to understand, similarly with Shakespearean english verses american english.
a changing language is inevitable, but will be countered by written standards. by enforcing those standards you can maintain a neutral territory for people to converse and yet they can go home and resume regional dialects for everyday conversation.
in the same way a changing culture is ultimately detrimental
um, no. language diverges from the norm making it harder for different groups to communicate. culture evolves to incorporate or exclude groups and ideas. I don't know that it is detrimental as it is just different. Diverging language doesn't really have a positive use other than alienation and separation.
Languages evolve to incorporate or exclude groups as well.
when you say Diverging language doesn't really have a positive use other than alienation and separation you make it sound like it's an invention or something that we can change. You probly didn't mean that, but I think it's important to say that language change is normal and regular, and trying to prevent language change is hard, and I think, counterproductive.