like, farm per day doesnt mean anything. If you clear someone and farm a decent chunk as a low point player you'll get boosted up once but that wont be consistent. And at a certain point, there is only so much res to farm, especially if you ahve to share it with the rest of OBEY, VAPE, SBAD....... Rimfarming is pisseasy, try getting the same score you got in the core and it's a totally different story
A low point player won't be farming enough with clearing a player to make it into the top 100 farm in a day.
You are right, there is only so much resources to farm in a certain area, however being an efficient farmer and being active will mean that you can farm more than your competition in that area.
Farm in a day gives an indication of activity, i'm not saying it means everything, it's just a stat which helps determine if the players in a tribe are putting in the effort this world or not as much.