Pathological customers are disproportionately attracted to low price points. Your post jives with the experience of literally dozens of companies which have told me the same thing: the more you charge, the better your customer pool will be at everything. They'll read better. They'll have a better understanding of, ahem, engineering reality. They'll be more patient. They'll have less viruses and hard disk failures. They'll be better at using the Googles. etc, etc
Reminds me of Dan Ariely's (and many other's) behavioral economics research.
There must be a deeper basis behind this. Some kind of psychology behind pricing. I've noticed it everywhere I turn.
One particulary interesting case was the packaging on Tesco (large supermarket chain the UK) branded toilet paper. It said it was just as strong and soft as Andrex, the leading brand. Andrex is much more expensive but still remains the leading brand!
I've actually been toying with this thought for a while and now it warrants much further investigation.
But it's very simple to say: "This product is cheap because it lacks quick response times for support". Most customers won't have a problem with that.
Once you pass a certain price point, you are generally dealing with an enterprise. This means 1) they are spending Other People's Money and 2) they are more likely to be accustomed to a professional environment.
The whole point in offering the discount is destroyed due to the financial cost of the headache involved.
People would call if there was an error in their ad. Companies who had paid for their ads were almost always calm and polite, people who got a free ad for a small value item were sometimes very rude or aggressive.
It is weird.