A useful link but note:
replya) the curve indicates 30s not 40s
b) there is no breakdown into theoretical vs experimental research, or scientific field; theory I would expect to be over-represented at the younger end especially as the science discipline becomes "harder".
Overall I would say it lends credence to the idea physics is a young person's game at the very highest levels.
a) the inflection point is in the high 30s. Further $\int_{40}^{50} f(x) dx > \int_{20}^{30} f(x) dx$.
replyb) true there is no breakdown but I would expect the exact opposite as fields get harder. More context requires more training and familiarity, which I would expect to increase age.
My point is that I think there's a bias in the field towards the youth narrative but the majority of discovery, even in physics, happens at a later age.