Most guys that play that badly either lose and don't come back or finally figure it out to the point of not playing the same( look for 50 VPIP players with 5K hands). If your at a stake long enough to follow long term losers for that long I would stop playing the table selection game and start playing tougher opponents. I don't believe anyone under $50NL should bumhunt anyway. I get that sometimes you need to have the table dynamic set up right with some fishier players on the right and tighter players on the left, but to actually look for fish at $2NL-$25NL is kinda pointless and will not really prepare you for moving up or getting better.