Consider the demographic submitting to NIPS. It's a self-selected group within the top researchers in the world in that area. The best people in the field don't want to be seen publishing the so called "second-tier" conferences, so they will submit exclusively to the likes of NIPS. And if you're an up and coming researcher or research group, you will want to establish credibility by publishing in these sorts of venues, and you will almost surely send your best work there. Add to this the fact that this is a "hot" field, so more and more researchers and research groups are getting into the field and trying to publish papers, I think it's very likely that NIPS gets a lot more good papers than they can possibly accept.
What does "poor quality" mean? There is no absolute standard for quality. "Poor" is something like "less good than usual compared to the recent work in this community". So the top-scoring third-ish of papers sent to the currently-converged-on favourite venue of a community are pretty much by definition not poor. Unless something very weird indeed happens one year. There are usually only very few really excellent papers, though. Most papers are filler in retrospect.
Also, conferences need to accept a decent number of papers so that people will show up and cover the costs of the meeting. Venues are usually booked long before the program is fixed.
Ok, we've gone from "top tier venue, basically impossible to have a large fraction of poor papers submitted" to "Most papers are filler in retrospect" and "conferences need to accept a decent number of papers so that people will show up and cover the costs of the meeting". I guess if I am deciding whether or not to hire a professor I would be tempted to disregard publications in this conference.
Number of publications is a proxy for how much funding a professor can generate. Not much else.
> "Most papers are filler in retrospect" and "conferences need to accept a decent number of papers so that people will show up and cover the costs of the meeting"
None of these are conflicting. Conferences are often more about networking than the papers. Many paper are filler, but often only in retrospect. They are not obviously filler when presented.
> I would be tempted to disregard publications in this conference.
That was not something I suggested. NIPS is very good conference, and a paper there is suggestive of quality work. Lots of past NIPS authors have been aqui-hired or regular-hired by Google and Facebook recently in their machine learning spending sprees, for example.
I think its a bit harsh to call the papers "filler", but the reality is that most papers (in CS, anyway) are incremental work on important but well-studied problems or work on problems that are fairly narrow or not universally considered to be important. Reviewers tend to have wildly divergent opinions on how important or interesting that kind of work is.
The "in retrospect" was an important part of that point. Reviewers don't have access to it when reviewing.
Some conferences and journals have a retrospective prize for the best paper of, say, ten years ago. It's a neat way to recognize papers that turned out to be useful.
