Since nobody is coming to your house to take your books, it is all additive. Soul jar, or whatever the term is, is just another word of phylactery. I mean, do you really think that everyone in-setting uses the same word for everything?
Every single thing in D&D is still there. New lore adds to it, even if the book says "we're changing things to X isn't true anymore; instead, Y is true." Because as I said, nobody is taking your stuff away. If you feel like trying to adapt THAC0 to 5e, go ahead. Nobody is going to stop you.