While I have the same intuition as you, I wonder if the author means other kinds of metal could be the bottleneck. Also, my intuition points that minerals are not a bottleneck if we can make it cost-efficient to extract extraterrestrial minerals (ie, asteroids and comets). But can we? 

Thank you Julia for this well-written post! I had been considering writing something along these lines (because of the increase in EAs working in policy and under public scrutinee), and I am very, very glad that this is not only taken seriously, but also actively being worked on.  

That is a great initiative! I'm a graduate student focusing on international relations, and it's not obvious what I should be doing next to maximise my impact. I'll make sure to look it up and contact you once I've gotten a few things out of the way.