In my 25 years of being a professional mathematician I've found many (though certainly not all) mathematicians to be acutely aware of status, particularly those who work at high-status institutions. If you are a research mathematician your job is to be smart. To get a good job, you need to convince other people that you are smart. So, there is quite a well-developed "pecking order" in mathematics.
I believe the appearance of "humility" in the quotes here arises not from lack of concern with status, but rather various other factors:
1) Most of us know that there are mathematicians much better than us: mathematicians who could, with their little pinkie on a lazy Sunday afternoon, accomplish deeds that we might struggle vainly for years to achieve.
2) Many of us realize that it's wiser to emphasize our shortcomings than boast of our accomplishments.
By the way: people quoted in this article are all extremely high in status, and indeed it's mostly such mathematicians who wind up talking about themselves publicly, answering questions like "Can you remember when and how you became aware of your exceptional mathematical talent?" Every mathematician worth his or her salt knows of Hironaka, Langlands, Gromov, Thurston and Grothendieck. So these are not typical mathematicians: they are our heroes, our gods.
It is nice having humble gods. But still, they're not stupid: they know they're our gods.
My experiences, as a kind of outsider who is just curious about some themes in math too and asks around for infos, explanations and preprints/slides, is that mathematicians are by far the easiest science community to communicate with. I conclude that status is of little relevance.
In my time in the mathematical community I've formed the subjective impression that it's noticeably less common for mathematicians of the highest caliber to engage in status games than members of the general population do. This impression is consistent with the modesty that comes across in the writings of such mathematicians. I record some relevant quotations below and then discuss interpretations of the situation.
Acknowledgment - I learned of the Hironaka interview quoted below from my colleague Laurens Gunnarsen.
Edited 10/12/10 to remove the first portion of the Hironaka quote which didn't capture the phenomenon that I'm trying to get at here.
In a 2005 Interview for the Notices of the AMS, one of the reasons that Fields Medalist Heisuke Hironaka says
(I'll note in passing that the sense of the "genius" that Hironaka is using here is probably different than the sense of "genius" that Gowers uses in Mathematics: A Very Short Introduction.)
In his review of Haruzo Hida’s p-adic automorphic forms on Shimura varieties the originator of the Langlands program Robert Langlands wrote
For context, it's worthwhile to note that Langlands' own work is used in an essential way in Hida's book.
The 2009 Abel Prize Interview with Mikhail Gromov contains the following questions and answers:
In his MathOverflow self-summary, William Thurston wrote
I interpret the above quotations (and many others by similar such people) to point to a markedly lower than usual interest in status. As JoshuaZ points out, one could instead read the quotations as counter-signaling, but such an interpretation feels like a stretch to me. I doubt that in practice such remarks serve as an effective counter-signal. More to the point, there's a compelling alternate explanation for why one would see lower than usual levels of status signaling among mathematicians of the highest caliber. Gromov hints at this in the aforementioned interview:
In Récoltes et Semailles, Alexander Grothendieck offered a more detailed explanation:
The amount of focus on the subject itself which is required to do mathematical research of the highest caliber is very high. It's plausible that the focuses entailed by vanity and ambition are detrimental to subject matter focus. If this is true (as I strongly suspect to be the case based on my own experience, my observations of others, the remarks of colleagues, and the remarks of eminent figures like Gromov and Grothendieck), aspiring mathematicians would do well to work to curb their ambition and vanity and increase their attraction to mathematics for its own sake.