Where’d that apostrophe go?

I want to say it was Mrs. Brogna, our music teacher and glee club director who also taught English when I was in junior high. It sounds like something she’d say. But it may have been another teacher. After all, I graduated high school more than 50 years ago.
The point, anyway, isn’t who said it, but what was said.
I could always draw and so it was not unusual for me to be asked to make a poster for a Halloween program. Before I began, my teacher, possibly Mrs. Brogna, called after me, “And don’t forget the apostrophe.”
I must admit at first, I wasn’t sure what she meant. Then it dawned on me. It was the old school way to spell Hallowe’en. There was always an apostrophe between the e’s.
I knew my English so I understood why. As with contractions like “don’t” or “can’t,” the apostrophe means there’s a letter missing.
The original holiday was called All Hallows’ Evening, or All Hallows’ Even. The apostrophe here was a possessive.
As time went on, the “all” was dropped, the apostrophe replaced the “v” and we had Hallowe’en.
Eventually it evolved into Halloween.
I’ve seen blogs suggesting we put the apostrophe back, but I cannot picture that getting much traction.
Besides, we need to save our apostrophes to use incorrectly when we want to make the word it a possessive. Like, the dog wagged it’s tail.

Ed Ackerman