I don't believe I am going to win the steel building in any of my cities. If a person plays the event, they should have the ability to win the set being offered if they complete all the quests. I will complete all the quests in most of my cities. I have one where I might not pull off 20 vision vapor--we'll see. But I do not believe I will win that last building that produces steel.
To say it doesn't matter is to ignore the fact that it produces steel and is a part of the set. To say it doesn't matter is to ignore the hours of jumping through quest hoops to get to the end of the event and find you are not going to win regardless how much effort you put into it. Would you display a teddy bear without a leg? I doubt you would. If I go through the trouble of playing the event to its end then I should have a path to getting ALL of the buildings required in the grand prize without spending diamonds. Everyone should.
I do not have enough "free" diamonds stored up to buy Sorcerer's Knowledge. I do not belong to any FS that is Gold in the Spire. I have 1 FS that gets Silver every week and I go to the top myself. But I don't get FS rewards for the Laboratory. I do not win enough diamonds in the globe in the MA to give me tons of diamonds. I use diamonds every time I play the Spire, and I use them when I need things in the MA that I can't win in a Spire that gives me mostly spell frags--things like artifacts to evolve my buildings. And sometimes in cities which are not in fully functioning FSs I use diamonds to buy Royal Restoration spells in the MA so I can upgrade buildings that are important to me. Not everyone is lucky. Not everyone is in a Gold Spire FS. Not everyone can get a stockpile of those "free" diamonds.
Why should I be penalized when I put forth the effort to complete the event? I can tell you that every recent event wears a little heavier on me. I get a little more tired, a little less happy with the game and the time I am spending playing it. I'm asking myself now why am I doing this, using my time when the rewards are not there to justify the expense. I used to look forward to events because they would help me grow my city and I would get good prizes along the way that would be beneficial to my cities. The events have been destructive to my cities for a while now. I have to spend time recovering that I never had to spend before. They are no longer fun. Just drudgery for drudgery's sake with disruptions to my cities. But at least there was the prize at the end. Without a complete prize at the end, is there any use in playing them anymore? I think not.