That's not to diminish Aaronson's generosity here, just to put it in the context of his actual career motivations.
Unless you have some deeper insights into his psychology, your guess is as good as mine: "Scott Aaronson is simply a decent human being."
The other thing I dont like about Aaronson is his weird fetish with STEM people , he seems to think scientists and technologists are somehow superior or more worthy than regular folk. I also dont agree with some of his opinions on the actions of the state of Israel, but I will avoid that, being this the Internet.
Your examples seem different from your law. Your law says that a more accomplished person can afford to be more modest, whereas your examples suggest that a more accomplished person automatically is more modest. While it would be nice if there were some such causative effect, I think that your examples in evidence of one are very cherry picked (and speculative: do you really know whether or not Einstein was a modest person?).
Given a different person, we may have read about "UT-Austin Professor and Quantum Researcher Finds Classical Alternative to Quantum Recommendation Algorithm" (with generic help from students in a footnote somewhere). It's great to see this type of collegial mentorship.