Most people find it hard to read books with long s, for example, or even know what long s is or where it occurs. "Why are all the s's replaced with f's?" people will ask. It's fine if it's "ash-tray" instead of "ashtray", but the further you go back and the more of these archaicisms you encounter, the more of a barrier they become to ordinary readers (instead of English majors). I don't necessarily like this kind of textual modernization, but in general it's necessary to keep the text accessible to moderns.