I don't think the main reason for most players who quite the Elemental chapter was because of the sentient goods. From some that I've heard there main reason was the total lack of expansions (1 in the tree, none from provinces anymore). And yes they had build there city to the max with premium buildings, meaning that to complete this chapter they would have to tear those paid-for buildings down. That's throwing away a lot of money, I would be angry about that too if I had spend so much money.Not sure your question really fits here but you know me, ill reply anyway
I think some players just quit because after a long wait to start the next chapter they found out to be stuck again because nog enough tree gum was being offered. That might have led to some frustration, but that was also the reason we had the long wait in the first place. I expect another long wait for T5 race to come indeed, and a longer wait for T6 race. Mainly because the long wait started an endless circle of players stopping, cause longer wait, causing more players stopping.
Personally i think there could have been better ways to handle the sentient goods. (like: you can produce them the whole chapter, but you dont really need them in researchtree or guestrace buildings untill the next chapter, only to upgrade your T1 factories to higher levels like it is now). You know there are also some heavy spenders on dutch who spend a lot of diamonds each time a chapter comes out. So it must be hurting inno as well by postponing these chapters.
There's also another reason (you know which ), but that would be off-topic and we are also not really allowed to talk about that anymore