I think a large part of the point in that part of the article is that the price gap between exchanges is much wider than it is for just about any security tradi

I think a large part of the point in that part of the article is that the price gap between exchanges is much wider than it is for just about any security trading on an established stock or commodity exchange (because the time and fees involved in exploiting that gap for Bitcoin make arbitrage hard to pull off, so the gap-tightening effects of it don’t kick in). You aren’t going to see inter-exchange differences of several percentage points in the price of a share, because savvy traders/trading bots would instantly jump on it and the gap would tighten up again.