Case insensitive FSs aren’t a new thing.
More precisely, they came up in a time where Unicode was not a thing.
Yes, you need to attach the locale to the filename. No, I have no idea off the top of my head of how different file systems encode or store that.
They don't. None of them.
Or, if it is, then let’s go back to eight characters from the English alphabet in all caps. 8.3 filenames. Why not? [...] Why are spaces, cyrillic, special characters and long names worth doing but case insensitivity isn’t?
Because you cannot have both.
It is either "spaces, cyrillic, special characters and long names" or case insensitivity.
The author of that paper hung around in the lang design forum were I originally presented this.