I mean, I agree that an NPC giving you a whole monologued spiel in response to you saying "hello" is also not immersive. I just don't think the Fromsoft way is particularly immersive either. To me it just feels like a design choice that Miyazaki or whoever wanted because it adds friction, like every part of the game has to actively fight the player. It adds to the sense of "this game is weird and difficult", but (for me at least) not really to immersion.

But then I don't really get that progression feel either. If it was the case that there was a timer built in, then yes I could see it. Coming back later and the conversation progressing because time has passed. But again, that is not what is happening in practice. What is happening is just going up to everyone and pressing A repeatedly until they tell you to go away. Maybe an indicator would be better, but I mean... in itself it's kind of unimmersive that you can mind read that the NPC has run out of dialogue. Though honestly, in a game that does not have dialogue options and has a completely silent protagonist I am unsure how immersive it is even possible to make NPC dialogue full stop. It may just be an unsolvable problem.

Also, none of this has anything to do with the quality of writing or voice acting. I really enjoy the characters in Fromsoft games, they're charming, unique and interesting, even small things like tending to end with laughter in various ways definitely adds a lot to the "strangeness" of these games and their distinctive vibes and atmosphere. Fromsoft do have a way of writing that evokes a mood that very few others can emulate. Closest I've felt to it was Withering Rooms. But that has nothing to do with the way it's integrated into the game mechanically.