All you are saying is that a person needs to be makir mekomo. If he’s takeh holding by arguing, he can argue, and if not, not. I just resent the idea that “Gedolei Hador” is a “concept.”
Gedolei hador is not a concept. I agree with that.
We generally know who to not argue with, by general consensus of the other gedolim. The person who all the other gedolim are asking their shailos to.
No different than the secular academia, where they know who the biggest scholars are, without anyone appointing them.