I read the post, and I wanted to put a bit of my input on the moderator age problem that you stated.
There's various simple reason as to why people who are 18 or older don't apply very often (and trust me, they don't.) When you hit that age, your life changes a lot. I was one of the few 18+ moderators at the time moderating the servers actively last summer, and I had absolutely no problem with it. When you reach 18, responsibilities start pouring onto you, and you eventually find yourself with less time to play Minecraft, let alone dedicate hours a week to actively moderating. The reason why players who are still within that high school age are the perfect fit for a moderating position (if they're mature enough, of course), is that simply put, they have the most time to dedicate. When you're 14 or 15, you don't need a job, which is something that can really damper the amount of time you put into video games.
One last reason, which may not seem very obvious, is that most players who are 18+ generally aim for a much higher position than moderator. It would be false to say that they ALL expect a higher position, but it's true that many wouldn't be happy with holding a simple moderator position for 6 months and no promotion to the Sr. staff side of things. Take a look at the general chunk of Sr. staff, many were the standout younger mods, and the rest are the older group of people. Go even higher to the admin team, and you'll find it's even more the case (with some exception of course.) Not only the active ones, I'm also including past admins and sr. staff.
Anyways, your generality of 16-30 year old's playing this game (the majority) is false. The majority is actually in the 10 - 16 range. It may seem the opposite with the amount of well known YouTuber's being older and all of that, but it's not.
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