147K coins? Then you are a higher age player who should know how to manage his/her coin supply by now. At this point, if you don't have tens to hundreds of millions of coins to spare you are doing something very wrong (which I'm going to take a shot in the dark without looking at your city, and guess that the issue is you rushed the ages, in which case this one is all on you imho).
I'll make an assumption, like you did, but assume your words just sound rude, and aren't actually intended as such.
Because actually, I've been where I'm at for a while. I've been building my GB and helping my guildmates do the same. So I haven't leveled in some time. I've also specifically been reading guides and watching videos for maintaining, rather than leveling. I understand where your example would apply, though. However, three other items in this event have asked for similar large amounts of coin, as do/did/does the story and side quests. On top of requiring expensive items be built (cartographers three times, for example, per many other threads I've read; or requiring the purchase of FP, as another example). Given that, it's not unreasonable to deplete the 300k once had by completing quests.
When not leveling, the quests are the "progression", if you will. And when any of the quests going on are requiring so much expenditure, you get depleted before you can complete a run/event/challenge.
I wasn't complaining for complaining's sake. And this event specifically asked for feedback. If the response was going to be "you should've known better" or "that's on you", then most people wouldn't attempt to provide feedback.