My theory is that most people who participate in GMATclub are over achievers, who have a history of above average academic/test taking success and intellect.
Therefore, the scores, test experiences, etc might not be a true reflection of what is capable to the average individual...that not just anyone can work hard, do challanges, standard CATS regiment, etc...and score in the 700s...that GMATclub is not a good sample set or reality.
Valid theory?