I would in principle agree with you, however not about English, mainly because it is now a language of international discourse of any kind, and it thus no longer belongs to the local speakers.
It now has a role Latin had until just a few centuries ago, and extrapolating a bit into the future from that example, will remain quite stable while your dialect, American, Australian, Indian, Jamaican, will change until it becomes another language entirely, no longer mutually intelligible with the other dialects.
If you want to participate in the international dialog however, you will have to learn International, which is now English including the differentiation of the theiy’res, even if your native language is English. Your grand-grandchildren may have to learn English like an Italian in 1800 had to learn Latin if he wanted to join the international discourse.
It’s super interesting to watch this process unfold right now!