Right off the top of my head I can come up with all sorts of factors that are totally neglected in this article, for example: Survivor Bias: the best and brigh

Right off the top of my head I can come up with all sorts of factors that are totally neglected in this article, for example: Survivor Bias: the best and brightest get promoted. This reduces the average 'quality' of the remaining people in the original pool, even though none of the people changed in any way. Lets say you have a team of engineers, and 5 of them just turned 40. One of those over the hill engineers just got promoted to be a VP, and another one leaves to be an independent consultant. Don't you think the two that left the team were probably among the best in those 5, and therefore were more highly paid than the other 3? The average salary of your 40 year old engineers just went down, even though the average salary of the original 5 likely went up by more than 300%.