Kirrawynne, it sounds like you worked really hard on the event. I'm sorry that you worked so hard then likely felt blindsided by the final requirement. But I think the situation you encountered with not having enough gold wasn't so much a problem requiring a lot of people to spend cash to finish. It takes time to build up materials for everyone. Completing events without having the ability to have the gold items (which are a normal requirement used in most of the events) will happen until players are able to begin accumulating them. All of us encountered this. It isn't just you being low on gold and the company setting it up for money. Early on none of us were able to finish events. It takes time to build a kingdom and become established.
I think it's nice that you like to figure out the events. Trying hard without expecting things be given is a bit more rare nowadays. But I believe the reason Spiritwind puts so much effort and time into making guides for each event is because of how intricate the events are and it helps us know what we will need. It can help us know if we need to sit out an event because we don't have the materials we'll need to complete it. I think most players would not continue to play without the guides. It would be too frustrating. It really is a fun game that they put a lot of planning, time and effort into. They consistently provide new content every two weeks. I don't know of many games that do this. I just think you need time to build your resources and may wish to take a look at what strategies would be of help.
One last thought, we tend to get resource droppers with rotating resources. There are always new players who need gold items, so we get gold droppers thrown in as event rewards from time to time. Spending real world money on a gold mine and two Wizard schools and even buying nothing else will give a big help. But you can choose to play without spending any real money. It will definitely be more difficult. But it's not undoable. I am sorry that you found the event frustrating. You may wish to wait on events and spend some time gathering materials.