Non-SEO's do not seem to complain about results much. I would imagine that a good test might be to get SEO's to judge results and non-seo's as well.
I definitely hear regular searchers complain, but not as loudly or as often.
One reason is that for many of them, it doesn't occur to them that there's any forum they should go to.
A second reason is that I've seen some research in the past that they blame themselves. The search failed because they don't search very well.
Personally, I think a bigger reason you don't hear this so much is because often they find stuff that's good enough. It's not the best -- but they aren't an expert in an area, so they take what they get and are relatively happy.
I have this canaries in a coal mine metaphor I've long used when it comes to search health. SEOs and librarians are the canaries. If anything goes wrong in the search engine coal mine, they know it first.
Librarians, because they are often experts in areas, use search regularly and understand if something seems wrong.
But SEOs intimately know the area they want to rank well for. Yes, some who are new may judge everything based on, "My site's not there, this sucks." But others will know the difference between their site not showing up and the results just generally not listing a variety of sites that should be there.
It's unfortunate that the group that knows search engines the best have this self-interest conflict that naturally makes people want to dismiss their concerns. I don't mean that negatively -- it's just a fact that if you're an SEO, and you point something out, someone's going to immediately assume you're upset because you personally don't rank well.