I think that the code to handle versioning and help text (except a brief usage message, which is often useful) shouldn't be included in each binary.

I agree that help text should be the purpose of the manpages.

A version number (or pointer to version string) could be one of the fields in the file header, to be read by a tool ("version"?) and displayed that way.

This way you still get versioning and documentation, without a massive duplication of functionality across every single binary.