You're a capitulating appeaser.
Whenever you try to make an argument for unfettered, uncorrected, mistake making becoming the new normal on the grounds that it's always happened, please try to consider the difference between a period without universal learning and without dictionaries giving spelling and definitions, and with foreign invaders bringing different languages in, and the period after those things all changed.
We don't hold to "scientific" ideas rooted in ignorance and we should not hold to the meanings of words changing because of it, as there is no longer any excuse.
Whoever was first to say "could of" when what they meant was "could have" was not engaged in evolving a living language, they were engaged in being wrong. They did it out of ignorance, and they added nothing to the language, they benefited it not at all. They just used the wrong word.
If you asked someone if they'd like a drink, and they replied "Yes, I'll of a pint have bitter, please", would you really think that was perfectly OK?
What if they were a non-native English speaker, would you ever, under any circumstances, consider putting them right, and explaining the difference between "of" and "have", or would you let them think that they were speaking correctly?
If the former, why?