[throwaway48476]

With community servers an admin only has to police their server, which is a fixed number. More players, more servers, more admins.

[ThatPlayer]

But as gaming has grown and become more mainstream, the ratio of enthusiasts who are willing to admin to casual players who don't has changed. Server sizes have changed over time with smaller games like 5v5 becoming way more common.

[throwaway48476]

Just put a password on the server then.