I know all of the participants in this drama. North and South have a detailed System Card as well as extensive notes. Chris himself is as straightforward a person as you will ever meet. I take his comments at face value.
Disclosure: I know North and South very well ...
Like Jim, I also checked my Masterpoint History. I earned some Silver points on 11/3/1991 and then some Red points on 8/12/2013. Even by 1991, though, I was only playing a few times a year.
Why? Family, work, tired of traveling to tournaments (cost etc.), other ...
Imagine an 11-table game with 10 very average pairs and 1 awful pair. The awful pair scores 30%. The 10 other pairs split the rest of the matchpoints and are all above average.
Edit: 11 N/S pairs. E/W pairs are irrelevant to the example.