@muffy. Tackle it from a different angle.
Maybe try looking at it in reverse? For example "What things would my city be missing if the Spire and everything that comes with it went away tomorrow?" Assume everything that is either only available in the Spire or greatly enhanced by rewards gotten in the Spire went away or were severely reduced:
#1 Diamonds (lol,
@crackie):
Spire is what lets everyone get a premium city without spending a dime. <I stole that line from someone else on here, but now I don't remember who
It's the diamonds given as both individual rewards and FS rewards as well as other rewards that allow more of other activities (like crafting) that also have diamonds given as rewards.
#2 Crafting supplies: way fewer Spell Fragments and Combining Catalysts. On SF's players would be limited to Moonstone Library, disenchanting, or the tiny amount of these given as event rewards. CC's are as limited if not more so than SF's. Most players already produce solely CC's in their MA's even with other sources. Those other sources (some event bldgs, AW's) For those who struggle with having enough pet food: think about not being able to craft it when it does show up because you don't have the needed ingredients for the recipe.
#3 Magic Houses and Workshops: You may not be getting many, but these going away as direct rewards added to the disappearance of diamonds directly from Spire. Couple with less crafting so fewer Mystery Object chances at diamond rewards and the only way you'd get a premium city without waiting a decade would be by spending real money.
#4 Temporary Military Boost Bldgs: no more Dwarven Armorers, but also less ability to keep crafting the other military boost bldgs resulting in more expensive tournaments/map encounters for fighters as well as for the more common hybrid cities who mix cater/fighting in a variety of ways. For me, this also translates to fewer supplies. I tend to use these bldgs as additional 'supply instants' after they expire. It's usually to push through a few more troops, completing the vicious circle, lol! I expect vicious circles; it's fun trying to work them into standard game play, lol!
#5 Teleport Spells: Way fewer of these; just a few from event rewards if there were no Spire. These allow me to play the game in a way that fits for me, my schedule and my life. Being able to swap bldgs back and forth from inventory based on my needs: wonderful. Being able to mold the game to fit my life instead of the other way around: priceless!
I could go on, lol! Cities just reaching the guest races need those extra PP's and the Trading Station that makes them; they don't get any until they unlock Ch6, so no stockpiles available. They are booby prizes to me: I think I have enough to get through any guest race chapter for the next 5 chapters at least...
With cities running on no houses, I've recently smiled when I win a coin rain in the Spire, lol. The coin rain purge of the July 2022 FA convinced me I never have enough coin rains! I spent hundreds of them, and even though I've got hundreds left, I'll not take them for granted, no sir, lol!
Edit to add: Consistency is key afaic. I've been tracking my diamond winnings since March 2022. 2 cities, one in weekly Gold Spire FS, the other in a Silver that's now getting Gold every 3-4 weeks. Some weeks/months have been slim, some have been outrageously high. The week of 7/18-7/25/22 for example I won 3245 diamonds. The ~1month from 6/15-7/11/22 I won not much more than that one week at 3870. The average monthly diamonds won as of Aug 23rd is 5583/month. Split equally between cities, that would be 2791 per city, but obviously the Gold Spire one actually generates more diamonds.