I think a few of them are inactive; not playing at the moment. Basically they have not gone to enough tournaments (....have not bought their way on the list[activity!]), even though they are better than a few people on this current PR list. Is it an accurate list showcasing the best players in GA/AL? Well, yes and no; I do think it shows a list of very strong players, however it does not show the best players.
Billy and BigLou are inactive. Saint hasn't been to an AL/GA tournament in a long time. Ragnarok said he's quitting Brawl, and he's been relatively inactive. 4GOD has been in FL pretty much all summer.
If you are an inactive player, we can't assume you are still better than the active players. Otherwise, someone could come to one tournament, get a good placement, then not have to come back and prove themselves again for the next three months. It's not fair to people who could potentially beat them at those tournaments. Things change and players that they used to beat will improve. In fact, to even say that we "know" these inactive players are better but we can't technically put them on the list is a lousy way to look at it. If they won't come to tournaments and prove that they still have what it takes, then they don't deserve to be on the list and they can't call themselves the best. Power ranked players have to put their skills to the test and put their ranking on the line every time they enter singles, else it doesn't mean anything. Inactive players shouldn't be allowed to sit back and hold onto their "top player" titles without any risk.