The reason why they went back to their word is because with the introduction of 3.0 the group wheel changed and they actually did not have a way to change the rewards on it (like they cannot change tomorrow the rewards of arena missions or the rewards of treasure huntings or ninja test).

They are not able to modify directly and first handedly any of the common core daily mechanics, to do it they have to request a core modification to tencent and very likely the cost to do it was too high, so they delayed it to the introduction of 4.0, when they got the big new patching pack from tencent, but at that point tencent told them how many new free power features were going to be introduced with it, so they chose to leave it as it was to leave some features available coupons only.

This is what happened almost for sure, but oasis won't admit it because would mean to admit they don't have full control of the game at any moment.