As you have seen several of the top ranked players have had upper level content cut off from them. While I'm sure the developers have a reason for this it's important to realize that you will also be cut off from the same high level content so it is important, if you enjoy the content, to stop purchasing gems to use for GENIUS Buffs. If you do that you will level up faster thus depriving yourself of the Fallen Content.
While you cannot cut off experience, you can maximize the amount of time you spend with this content by just not purchasing gems to gain more experience. While the problem won't be solved, it WILL be mitigated and put at bay for a longer period of time.