In the extreme case (the empty program), there is no more code left to remove. It suffices that any proper subset of the code is insufficient to provide the needed functionality, though.

> It should be considered finished.

And yet you obtain a cleaner version of the finished program by adding superfluous code to it. In fact, every unfinished version (a version where you can still remove code) of the program is cleaner than a finished version (where there is no code left to remove) of it.

> Not true in my experience. Unfortunately.

Removing the code is reverting back to the previous version. How is that not easy to do?

> Sometimes it's necessary to add some code, e.g., a new driver for a new item of hardware. I have nothing against adding, per se.

But that changes the requirements, and thus changes which code can be removed.

However, the point was that you could obtain an arbitrarily clean version of a program by adding redundant code to it—since it's easy to remove that code, it is cleaner than the irredundant version of the program.