I still farm AI3 for the rares. Also, now that you have most rares - this might be rude, so forgive me - it might be understandable you ask for them to stop farms. You could convince them to make it all HARMS, but the rare-giveaway would not stop. Also, there are rares the T50 refuses to use, as in, poseidon (you almost don't see it), fahrenheit, Morning Glory, SoG's are hard to get, SoR's are hard to get, Arsenics are rare to get, Titans are meh, And it changes everyday.
As it has been said, no one wants to grind the AI3 for 1 month just to build a FG farmer.
For example, one of the best farmers, CCYB, uses 6 SoG's. Where would newbies (A.K.A me and a few others) would get them besides t50 with a GOOD rate?
Also, if I ever, ever get to t50, I will but Harms and Farms, thinking on how much they helped me in the start, and I will hope to help the newcomers too. That said, with the upped cards, t50 itself is pretty hard to beat depending on the deck. Not all decks in T50 are farms or harms.