I think it should be brought back into context, most people knew at the start of the event that it was highly unlikely that they would get the third building without spending diamonds because we've had this before with other events. Everything we got out of it in the way of relics, kp, culture and culture/pop buildings was for free, there was no need to spend money on it at all, the buildings gave considerably more culture or culture/pop for their level than anything we could build ingame for free.
There was a really good spreadsheet which was done on the Beta Forum by SoggyShorts which helped tremendously with prepping for quests plus various other places where we could see which building was on which day.
All in all it was a good event, and it was FREE to do, no cost involved unless people wanted to. Rather than forever complaining about what wasn't possible to get without a lot of luck or money, perhaps it would be better to be happy with what we did get?