I think you are reading too much into the term 3A. I used it because I was lazy to write three names, when one can include all of them in one number and one letter. I never in any of my post mention anything about conveyor bell, so that’s meaning which you attributed to it yourself. Don’t try to attribute your thoughts to other people.
Nevertheless, you are right that Kostornaya did not revolutionise figure skating, because she has shown only triple axel and that has been already done. However, Trusova and Scherbakova definitely did manage to revolutionise skating, because doing quads, especially several of them in one program, have not been done in senior ladies before. So even though Yuna has much longer career, I would say that Scherbakova and Trusova are written in history much more even if they retired tomorrow, because they moved skating much further than Yuna ever could.