Given the normal distribution of intelligence, sanity, etc... an ~1/3 failure rate seems reasonable. Some people are disinterested in the topic, fairly stupid,

Given the normal distribution of intelligence, sanity, etc... an ~1/3 failure rate seems reasonable. Some people are disinterested in the topic, fairly stupid, poorly educated, but unaware of the (lack of) value in their views... and are all too happy to share them when polled.