Cores are the main commodity of Cabal. It's the most item traded by players; either bought or sold and it is also the most dropped item in the game. In fact, cores are the only reason that keeps Cabal's economy stable. How is that?
Let's say you have some cores, you either will use them to upgrade an item or just sell them to get some alz.
If you have enough alz, you will use them to upgrade your items. But with the low success rate of the Cabal's upgrade system you might not reach the upgrade level you want. Then you'll have either to farm more cores to keep your alz under your hand or (as most of us do) you will buy more cores. This means your alz will transfer to another player who had to sell his cores because he need alz.
After using your cores, you either reach the upgrade level you want or fail to do so. Either ways you will be short in alz, so you will sell you're farmed cores to another player who wants to upgrade his items, and hence his alz transferred to you.
By this mechanism alz is circulated between players and no one stays bankrupt for a long time.
Let's imagine if the upgrade system has more success rate. This means you will reach your desired upgrade level easily with less cores, which in turn will lead you to have abundant cores you don't need and hence you will try to sell them. But how can you sell them if the other players have already as well reached their desired upgrade level and they also have a lot of cores they want to get rid of.
This eventually won't make alz circulated as the activity of buying and selling has stopped at some certain point. This will lead to have a bunch of players holding in their hand a huge percentage of Cabal's liquidity. This will lead players to quit as there is no way to get the items they want except as a drop.
Game will die this way.
I (and may some of you after reading this) concluded that the upgrade system as it is now is important to keep the game alive.
However, while this current upgrade system is intended to keep the game alive, it forced many players to quit (even to destroy their epic items as may some of you have see). It is useless for them to go nowhere however the attempts they have tried or precautions they have taken.
The Game tried to solve this problem with a profitable solution: Safe Guards. But the more safe guards are offered the more the game is reaching to its end.
Est must find another way to circulate alz. They have to be creative about that if they want the game keep going on. I don't know how, I'm not the producer.