Re:post #30. That is impressive, as apparently only 5 perfect scores on the putnam have occurred in its first 82 years (through 2019).
In these discussions of Hilbert, I am reminded of the famous saying that he apparently did not know the definition of a Hilbert space, which does occur on some exams. So it is easy to ask a question in a way that will be challenging. Galois probably didn't know what a Galois goup was either. And Euclid probably couldn't define a "Euclidean domain", etc...
Re: post #29: I don't think it would be hard to find people who know a lot of those areas. I myself know "something" about 20 or 30 of the 60 pure math areas, and I am just an average low level retired mathematician. I have colleagues from my own school who know far more, and people like David Mumford or Curt McMullen, or Robin Hartshorne, or Yuri Manin, or John Morgan, or Jean Pierre Serre, know essentially infinitely more. Given the opportunity, and 50 or 60 years devoted to it, one can learn a lot. Some of us spent our lives teaching calculus over and over, but some people at elite places spent decades pushing the boundaries.