You actually make a fascinating point here. I did a statistical analysis of the ages of nations left in cn a while back on the NSO forums, and found the results really interesting. I looked at the makeup of CN based on age broken into iirc 2.5 year age ranges, and while obviously nations under 2.5 years was the largest group, nations 7.5 years+ was a larger group than either 2.5 to 5 and 5 to 7.5 iirc. The middle 5 year range definitely was low. It was a significantly uneven distribution.
In other words, there is almost certainly a correlation between nations having been around to experience these harsh terms (let's be real, we haven't seen really harsh terms in over 5 years, and that 7.5+ was back when tame terms would make Methrage come out of the wood work screaming bloody murder by today's standard) and longevity playing the game.