Mao does not do a lot of toe jumps I noticed. If she went for a 3-3 it would be with a 3loop on the back end of it and that's so easy to get downgraded on. Plus she does not do any lutzes in her program. Her 3f-2lo-2lo gets both loops DG in competition a lot, if only should could turn it into 3f-2t-2lo she might have a better shot. I think the reason Mao does so many 3a attempts is that she needs those points to points to be an OM contender, because she has no lutz, no 3-3, and a 3-2-2 that isn't very strong.
Skaters like Yuna, Miki, and Rachael have learned how to get the most points without being super risky like Mao. Rachael has a 3f-3t, and a 3lz-2t and 3f-2t-2lo planned late in the program which earn her a lot of points. Yuna's 3lz-3t (10 points) is worth more than Mao's 3a-2t (9.5 points) and she is much more likely to land it. Yuna also has a 2a-2t-2lo, and a 2a-3t late in the program. Miki has a 3lz-2lo/3lz-3lo, and a 3lz-2lo-2lo late in the program which she usually does not get DG on. Miki and Rachael attempt two 3lutz and two 3flip in their programs and Yuna has two 3lutz, one 3flip, a 3-3, and a 2a-3t. Joannie also knows how to rack up the points because she has a 3lz-2t (even that combination is not worth much less than a 3a) and a 3lz-2t-2lo.
So basically, there are other ways to earn lots of points without planning 3 super risky triple axels in your program. The others have figured this out, but Mao either has yet to or doesn't have much else to rely on