As is typical of these sorts of events, the overall design simply hasn't been thought through. Nobody has sat back and looked at the project as a whole.
For example, what is the point of having a quest that rewards you with 400 granite only to have a later quest where you have to pay 3000 granite? It just makes the quest and rewards utterly pointless. Things like this make the whole event into a mindless: "oh, I have to pay/build/do this now, click tick, next?".
There's no sense of fun. There's no sense of rising achievements/difficulty. There's no design plan.