The Shining is one of the most heavily analyzed films of all time, for good reason. It's not just some random Michael Bay flick. It's really almost unbelievable how deep the rabbit hole goes, so no, it's not surprising in the very least that people would spend time on a detail like this. If people 100 years ago weren't doing this kind of thing with films, it's because they didn't have access to films the way we do today, if The Shining was around 100 years ago and people had home computers they could play it on and could download it easily over the internet, you can be sure people would be analyzing it like crazy back then too.