Erdos isn't a counter-example to anything. I mean I agree with you. Old people can do math. Look at Yitang Zheng. But Erdos is the exception to every rule ever.

Doesn't that make him the counter example to everything :)

Yitang Zhang, not Zheng.

Oh darn it. I originally spelled it Yiteng Zheng..I caught one typo. thanks

G. D. Birkhoff proved the Ergodic Theorem when he was nearly 50. It is one of the high points of twentieth century analysis.