There is a likely a distortion of how wide spread this problem is. It seems that people are much more likely to make a post or write a review of a product when they are dissatisfied than when they are 100% happy with a product.
How often do you think a customer service rep gets a call to tell them how great their product and/or service is?
This has been mentioned in many posts, but you also need to consider your sample here. Most people here on MR are likely far more into their devices than the average consumer. Therefore, it is more likely that MR members are going to run these "tests" to check out their screens. Perhaps this is an "ignorance is bliss" situation, but at the end of the day there are probably far more people who are happy with their Air than those who aren't.