You’re going at this from the wrong direction. NES hasn’t played in a long time so there’s a high degree of uncertainty around his results. He absolutely should be ranked lower because without him playing in tournaments it’s impossible to know how to rank him accurately.
If we went back to his last 20 appearances we’d have to go back more than 5 years. That would bring around a lot of uncertainty. Players would be outranked by someone who had a bunch of good finishes 5 years ago, but haven’t played in any events for a year and a half! That would be a terrible ranking system.
Unless of course you’re trying to determine the best players over the course of the last 5 years. But that’s not what IFPA is trying to do. IFPA is trying to determine the best player right now. And for that, you need to actually be playing right now.