Why do anglophones confuse "it's" with "its" so much often? I mean, I can understand if it's a distraction mistake but I don't know if this is still a mistake or has become an actual rule to put "it's" as a possessive adjective instead of "its", because I even saw the use of "it's" as a possessive adjective in a footnote of a US website a few days ago, so I don't know if this became part of the language. However, to my knowledge, "its" is the correct possessive adjective, unless I'm proven wrong.
Why do they get it wrong?
- It's a complicated rule
- It's the opposite of the regular apostrophe rule ("The house's door is green.", but "Its door is green.")
- The regular apostrophe rule is itself complicated enough, without having to learn an exception to it.
- None of these rules are taught in native English-speaking schools except at the elementary level, after which they are forgotten.
- There are so many examples of poor apostrophe use, even by professional writers, that most people aren't aware that they are making a mistake, And if you believe that "correct English" is defined by the people who use it rather than a few people who write grammar rulebooks then maybe they are right.
I don’t think it’s become part of common usage, see the following comment from the Grammarist:
Most English speakers are comfortable with the difference between its and it’s, yet even the most careful writers mix them up in careless moments. Such errors are typos, not grammar mistakes (there is a difference), and can usually be stamped out with a quick proofread. None of us is immune to these mistakes, so let’s not be too hard on people who make the occasional its/it’s slip-up.
Also from M-W
We still see the possessive it's in dashed-off tweets and in flyers from local mattress stores, but the fact that it was right 300 years ago doesn't make it correct today. For those of us who live — and write — in the here and now, use it's only when you mean it is or it has. And drop that apostrophe everywhere else.
When you are confused write it out: If the fully written version is "it is" or "it has", then write "it's", if it does not need the "is" or "has" then it is a possessive and no apostrophe is to be used.
It’s is a contraction of “it is” or “it has.” Its is a possessive determiner we use to say that something belongs to or refers to something. and its is a possessive just like “my” or “your.”
I cannot think of a language in which 100% of the speakers speak and write the language perfectly 100% of the time.
Over 2 billion people speak English, making English the largest language by number of speakers.
https://en.wikipedia.org/wiki/Languages_used_on_the_Internet#Content_languages_for_websites: Languages used on the internet
Statistically, the number of mistakes/typos is proportional to the number of words written.