> not some sort of immutable feature of the universe
Except it is. Running your own server will always be more work than letting someone else do it, so unless there is a strong incentive people will let someone else run their server.
This is basically the Law of Leaky Abstractions. At some point you will have to deal with a problem yourself because no abstraction is perfect.
Why is there a graphical installer for the Minecraft client and not for the Minecraft server? Because of some fancy Law with Capital Letters, or because more work went in to the former than the latter?
Except it is. Running your own server will always be more work than letting someone else do it, so unless there is a strong incentive people will let someone else run their server.
This is basically the Law of Leaky Abstractions. At some point you will have to deal with a problem yourself because no abstraction is perfect.