Admitting one's limits is a necessary precursor to wisdom and understanding. If there are some things that are beyond our capacity to ascertain, we should admit that.
Well, Hasbro and WotC can do survey work, at least. Not quite as accurate, but sometimes you take what you can get. But still, surveying on the appropriate scale is also beyond our means here on this site.
But, let me answer a question with another question - Why do we want to talk about "quality"? Or, more specifically, why do we want to assert we know "quality"? In what ways is talking about our opinions and experiences insufficient?