I don't think that that really collides with @Otome-chan's point, which is how much power Ernest has. She's saying that Ernest can't really do what spez is doing with Reddit. Spez controls Reddit in a way that Ernest cannot control kbin, or more-broadly, the Fediverse. Spez could simply deny access to Reddit to third party clients.

There are people who are going to be writing guides and packaging the software. There are a number of kbin instances that Ernest does not personally control, not to mention compatible software. The bar will continue to lower, but it is already low enough that if Ernest cannot "turn off" kbin if there are sufficient people who want to use it.

The overwhelming majority of people in the world cannot deploy or maintain an email server either, if you asked them to do so off-the-cuff. But there are many people running email servers around the world, and many people who can and would do so, were the need to arise. No one company "owns" email and can simply deny access to it because of that.

The point is that kbin and lemmy and such operate as email servers have, or Usenet servers, or IRC. The source code to servers is publicly-available and could be forked, if the need arises. Many different organizations run their own servers. And no one person can deny access to the system.