The last time I calculated all my results at 8/16 in Southern California, played at 5+1 rake, I was at about $14 an hour after 2,700 hours. And I'm probably in the 99th percentile compared to the 8/16 player pool.
Having said that, I don't really consider the game "beatable" because (1) you have to be in the 99th percentile to achieve that sort of result and (2) your expenses (which include the fact that you don't really get free food except at the Hustler) are going to cut into that rate to the point where you should probably play 20/40 if you are that good.
I still play 8/16 for funz sometimes, though.