It sounds like you're mostly referring to UX. I share the impression that there's a lot of research in this area that rarely seems to be applied. One reason for that seems to be because people are lazy and/or too content with mediocrity. But the main reason seems to be just because it requires a lot of expertise. Which means either taking the time to train yourself, or pay others. Depending on your intent, this isn't always worth it (but I think people very much underestimate how "worth it" it is).
So I'm working for a friend's company at the moment (friend is a small business owner who designs websites and a bit of an entrepreneur) anyway, I've persuaded him that we should research the empirical literature on what makes websites effective (which we've done a lot of now) and to advertise ourselves as being special by reason of doing this (which we're only just starting to do).
One thing that I found absolutely remarkable is how unfilled this space tends to be. Like a lot of things in the broad area of empirical aesthetics it seems like there are a lot of potentially useful results (c.f.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3485842/ ), but they're simply not being applied- either as points of real practice or of marketing differentiation.
A fascinating gap.