Careful: If you go by "longstanding behavior" instead of standards, you quickly get to the point where you have to ask yourself the question which longstanding behavior you want to honor for "consistency". This may not universally be true, but in the case of the shell(s) and everything that surrounds it, I'm pretty sure it is.
Shells are pretty much the wild west out there. I wouldn't be too surprised if some AIX shell variant or something came along and consistently bails out with an error when any argument is given to 'true', including --version. It might not be a common shell variant for you, but it might for other people. Hence, standards.
I'm not really arguing in favor of --help and --version to 'true'. I just don't see much of a problem with it.
Shells are pretty much the wild west out there. I wouldn't be too surprised if some AIX shell variant or something came along and consistently bails out with an error when any argument is given to 'true', including --version. It might not be a common shell variant for you, but it might for other people. Hence, standards.
I'm not really arguing in favor of --help and --version to 'true'. I just don't see much of a problem with it.