in many cases trying to incorporate [irrationality] reduces tractability to such an extent that it isn't worth it, or at least we don't know how to incorporate it.

This is true, but it's also worth emphasising that in many cases, we do have reasonably tractable micro models that incorporate irrationality [ETA: I should instead have said nonstandard preferences; not all of these are necessarily irrational], and they do get used. (I'm not suggesting you disagree with this, I just don't want to give casual non-economist readers the impression that the discipline as a whole blithely ignores such things.)