The shells have no relation to man, except that being programs they typically have man pages. When you run man, it parses some file (often using nroff) and outp

The shells have no relation to man, except that being programs they typically have man pages. When you run man, it parses some file (often using nroff) and outputs it to standard output, usually through some form of pager. A shell can't "move away" from man. It could ship with its documentation in a different format, or the authors could even develop a new documentation reader... but if you think man and the shell should somehow be specially related, you're forgetting how Unix works.