I highly doubt that anyone considers Mao one of the greats based solely ... It has more to do with her longevity/medals/style/impact on the sport in Japan and elsewhere than with one single jump. ...
I agree, I really admire Mao for all the other virtue you mentioned here. But 3A is the deal. just imagine a Mao without a 3A, with all the other stuff she does, what will her status be. or imagine a Mao with perfect 3A (not 2-footed), what will her status be now.
Regarding young skaters, it is just a stats.