I'm of the same mind regarding Thor. There shouldn't be a "new Thor" because Thor is not a title; Thor is a person. There can be a new Black Panther, a new Iron Man, a new Captain America, because those are all titles. I think it's dumb that they pass the title down at some point, but I guess it makes more sense than the character being around for 80 years or whatever and it's still the same person. At some point "they" (comic books in general) decided that titles/characters can be passed down, and since the MCU movies do follow many of the conventions established by their source material, it's okay.
But Thor isn't a title, Thor is the son of Odin and Frigga, a specific person. Someone can be the next King of Asgard, or the next God of Thunder, sure. But the "next Thor"? No.