No, and they've specifically specified it as always available. Just as GCC still supports C89.

However, they also specified this as only affecting translation/desugaring, which makes the additional code minimally invasive.

Epochs are primarily deprecated syntax behavior, so it's more like branches in the parser or other relatively self-contained bits. As the RFC says, the core language will continue to stay the same.

So I don't see this as leading to some major accumulation of cruft.

I work on the C# compiler and the answer over in that world is "no"; everything needs to be supported.

Perhaps it could move them to packages as compiler plugins? That could be more or less tricky depending on the piece though.