> Most of us are aiming for under a half second total for response times.
I know people working on that exist. "Most of us" is absolutely not, if they were so many, the web wouldn't be like it's now.
Anyway, most people working towards instantaneous response aren't optimizing the very-high latency case where the article may eventually get a 0.5s slowdown. And almost nobody gets to the extremely low-gain kinds of optimizations there.