I also think we need other ways to get coin as I do not like the idea of footfall
It may be possible this is by design and the devs want guild buffs to be non-sustainable, either as a way to reduce the total amount of coin in the game (if they are unhappy with that at this time)
or they are trying to make it more of a whole guild effort and not just an leadership effort, to sustain the buff.
or maybe this buff just needs to be treated as a luxury function and have to accept the fact that the buff was not designed to be sustainable all of the time, and then that requires planning of when to turn the buffs on and which ones.
Or maybe I am wrong and there was less logical planning put in to the cost, and the devs failed to balance the cost.