That's technically true, but most average users probably don't care. It's like optimizing your car's fuel efficiency by changing your spark plugs more often. When was the last time you changed your spark plugs?

Well, what actually happens is that there's less pressure on web developers to make their sites faster (in contrast to other business goals) and so we reach a new equilibrium where sites perform just as badly.

Web developers aren't alone here, of course. It's the same story for systems software as well.

In general, thinking in terms of equilibriums is helpful.