The problem is that there is no universal "currently accepted way of doing it". What you're describing is a dialect. It's sometimes reasonable to say that a certain use is wrong in a certain dialect, but insisting that a certain use is universally wrong is just insisting that your dialect is somehow more authoritative than other dialects.

There is no absolute prescriptive authority on the English language. It just doesn't exist at all. The common English dictionaries don't claim to be prescriptive authorities, they claim to describe how the language is currently used. If there are any English dictionaries that claim to be prescriptive authorities (I don't know of any off the top of my head), they're clearly completely ignored by pretty much the entire world of actual English speakers, so their authority isn't worth very much.

I strongly disagree that slowing down the change of language is nearly entirely good. I think it's neutral when it's a natural slowing caused by cultural shifts, and I think it's strictly a bad thing when it's a forced slowing caused by active gatekeeping from self-appointed dialect police. Language is inextricable from culture, so language change is inextricable from cultural change, so language conservatism is a form of cultural conservatism.

If I had a crystal ball and I looked a couple hundred years into the future and saw people speaking the same English that I speak today, I would be terribly sad about English-speaking culture. I sure hope we have new ways to talk by then! I also think you're dramatically understating how much English has changed in the past couple years - while English from the 1700s can mostly be deciphered by modern English speakers without a complete re-translation, it certainly doesn't read fluently to a modern speaker, and it's missing a whole lot of the words and structures that people use to express their modern concerns. This is all normal and natural for a natural language.