>If competition is somehow the opposite of "centuries of traditions of open science", and "mathematics has always been highly competitive", then open science is neither sufficient or necessary for the future of mathematics

For the future of past mathematics, it says nothing about the current future. Also, open science can be nonsufficient and unnecessary but still extremely beneficial and desirable.

>Their clear implication is that we don't need to worry about it, though, because it's always been that way.

Lets just ask him if that's what he meant, I bet no.