Does getting an undergrad degree in astronomy and physics, and then a math PhD from UIUC, really count as "blooms late"? Sounds like a fairly standard career path to me.
If you like this kind of story, I highly recommend putting Quanta (https://www.quantamagazine.org/) on your radar and avoiding most of the tabloid-science articles in Wired.
I personally know several IMO winners who started studying Math when they were 3~4 years old and it's been part of their life.