Agreed with what you said, when you're only considering security and usability you're often not at a Pareto optimal state, but once you add cost into the picture you see a lot more cases of being on the Pareto optimal boundary, or at least in case where the next improvement only comes with significant effort (by re-platforming, for example).
I guess that makes sense. as you get to higher dimensions, most points sit very close to the surface. So if we're trading off N things and N >> 1, expect to basically always be at the pareto boundary.
Yes, I don't mean to imply that this is some sort of clear majority situation or anything. I just mean that I've definitely both seen on HN and participated in real life in some conversations in which it was taken as given that we must give up one thing to get another when nobody had in fact established that we were on the Pareto frontier. Or, considered from a local point of view, whether the tradeoff really was inevitable. I have had cases where we could have had both, with no difficulty.