Ha, good point! I once met a queen and I addressed her “Your Majesty”. My only excuse is that these rules are older than both of us, so it’s not like I was obeying her recent whim inspired by Twitter.
Last time I met a priest, I called him by his first name, because he was my former classmate. I don’t remember talking to a priest before that. My guess is that if I met a priest today, I would likely call him “father X”, simply because that’s how he would likely be introduced to me.
To me, religious and aristocratic titles are “job names”, kinda like calling people “professor” or “general”. And they are supposed to imply higher status… at least in eyes of those who respect the job. (Also, they are not pronouns, so the usage is a bit different. In the previous paragraphs I have described the queen as “her” and the priest as “him”.)