Let me remind you that most players in the community are around age 13-15, thus the age limit, to apply for Moderator, starts at a reasonable age of 14 years old. This being said, it is expected for moderators to resign more often, or quicker because players move on, because they need to monetize their time, or they need to focus at school.
Most of what you explained focuses on psychology, but often people don't know what really is happening in these peoples' mind. For some, this includes some of my friends or people I know, becoming a member of Staff is an achievement. More than applying for moderator to help others, they apply because they think its time to do so, because its time to step the game up.
You see, these people don't want to be forgotten and stay forever on the halcyon days; they want to be remembered, whether as a Staff or VIP, because once you spend so much time on a community, it's easy to be forgotten.
To understand someone's mind, you need to first understand and take the input of other people. What other people do on an environment determines the actions newer staff will take; this is just how children often mimic their parents, because their parents are older, have more experience, and the children think its okay to take the same path.
I think that we tend to say that the staff team went downhill ever since 2014, but we also forget that there will always be someone better than you. But also this correlates to what I initially said: Moderators resign more often, or quicker because players have other things to focus on. Because moderators leave the staff sooner, than what moderators in the past would last, this also means that our current moderators have less experience. So, simply, its not that the current staff, or the staff in the past year, is/was bad, it is that the staff doesn't have the same experience as the current generation of players move on faster.
Writing threads is nice, but instead of staying subjective, I think its important to research a topic before-hand. If I were you, I would have interviewed ex-staff that just resigned recently and why they resigned, and interview older staff. I think that everything has to be substantiated. I tend to analyze things, and sometimes if the argument is good enough, I can believe in it without it being substantiated, but this is just normal.