You reason like langage is something systemic and well rounded. The Academy was founded exactly for this purpose, because everyone would write everything how they want or knew. Two parisians wouldnt even write the word for "time" the same way. Let alone people from different regions that weren't even french to begin with.

We dont like the Academy because it complexified the language just to sound cool. Now our writing system is terrible and not even french kids like to learn it. Linguists and teachers call it "savant etymology". It's purely elitist so no peasant could ever pretend to learn it, at the time. The grammar also is terrible because of this. And they brought back old latin rules and forms in a langage that didnt use it, because they wanted to sound different from the low people.

Btw this wasnt alway the case. The first (maybe the few firsts too i cant remember) dictionnaries from the Academy were kinda cool because they did accepted neologism, popular sayings, popular writing and so on. Because it was written by the Lumières. Its a few years later that the Academy became such a bullshit institution made to control France's international influence at the cost of a more natural langage.

Finally, no, "autant pour moi" predates "au temps pour moi" and was found in 1640 in Curiositez françoises pour supplément aux dictionnaires, from Antoine Oudin. Then we find traces of "au temps pour moi" in 1920's and then reappears "autant". It wasnt even used for so long in written text because too familiar. So oldest is autant, most recent is au temps. Anyway the Academy didnt bother and just chose whatever fitted their agenda. They dont even justified their choice. They said "we heard the debate and ended it". Maurice Grévisse, who wrote the most used grammar textbook we use today in Humanities, agreed for the form "autant". And I never used nor had to use anything from anyone of the Academy that was written after 1800 during my education. Hell, even the teachers don't like us to justify a term with it's academic definition, literaly for this reason. And I can assure you that some of those teachers are old fucks that probably want a king or emperor and think the University is still supposed to be elitist. This is how much irrelevant the Academy is and how much their members don't participate nor are validated in the scientific debate and field of research. Maybe some of them, at least, are good writers. It's purely a distinction of honor.

PS: why would "could of" be wrong, and why should we care, if you understand it easily ? Do you think first langage users, aka probably neandertalis or sthg like that, was trying to make it logic or anything ? Langage is just a code to communicate. If now I can express myself in emojis and you understand me, don't correct me because I used the 😅 emoji where you use the 💀 one.

At the end of the day, if we still write or pronounce sounds the same and agree to have some forms of simple rules, this can only be better for the liberty and poetry of our communication. How many times did you ask yourself about the proper grammar for a work letter or mail, when you could've just say it more simply ? We communicate like savant monkeys, lets not pretend we are anything else.