>>> "SM" == Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> GNU Emacs runs on free and non free OS, so although that is important
>> point I don't think it is essential.

> But Emacs does not work better under Windows (or macOS) than under GNU/Linux.
> E.g. we explicitly disabled support for colored fonts on macOS until we
> had support for that under GNU/Linux.

> So a comparable situation would be for a mode that works both with
> Matlab and Octave but doesn't provide any feature which only works
> with Matlab.

I am not sure that the  command-shell would fit into that description. 

Frankly, I don't see here a problem, in my understanding currently we
have

    1. One shell for octave

    2. One shell for matlab

It would be different, if there were only a command shell for matlab and
none for octave, but that's not the case.

Whats about my argument, a matlab mode for emacs, could encourage users
of the internal non free matlab user to switch to GNU emacs (and then
potentially could contribute either by bug reports, fixes or even more
features...)