Or maybe language changes, styles change, vocabulary changes, society changes... Language isn't geometry.
I personally find the insistence on "good English" in some threads to be detrimental to English learners, my own personal view on such a conceptualization of language aside.
There are many rules that are flexible and not really rules at all but rather patterns of speech. Many learners who become fixated on "good English", in my experience, end up being too perfectionist to the detriment of their learning. They fear writing, speaking, and generally using the language, which is the most critical part of learning a language. Rather than aiming for understandability and practicing using English even if they make mistakes, they get fixated on finding the "correct" tense or the "correct" article and get stuck. It also makes them extremely frustrated because in many cases there is no neat rule to memorize.
- For Teachers