In reply to Klaas.

Interesting question. Why would the average user know what to do when a plugin is no longer in the repository?

You are trying to present an unrealistic argument. If someone is working with plugins, and they need to know if they are no longer in the repository, then they have to know what to do if that plugin is no longer available.

To use your argument, we would need not only automatic updates, but also automatic replacements. I suggest you are creating a separate problem.

The problem is solved with plugins.