why was the supports gold gain nerfed so much?

I don't think supports should be making so much less gold, especially if you are behind it makes it really hard to come back. Now when i'm behind it takes 20 minutes to build one item and by the time it takes for me to build that item it becomes useless because the enemy has 2-3 items already. I find that playing support now you either have a really good laning phase and you can help your team later, or dont do well and become useless all game. I feel like spell thief's should still make passive gold because if you are fighting a zyra or brand support you cant really poke them without getting punished hard.