Besides uncached views (I'm guessing a decent amount of the traffic from HN for this submission would be) you also have to consider parse/eval time. Look at the flame charts in Chrome Dev tools for some of your favorite sites and probably see a few that take almost a second to parse/eval cached JavaScript. It will be even slower for mobile users.
Just because it can be cached doesn't mean it's free or even necessary.
Just because it can be cached doesn't mean it's free or even necessary.