I agree with the sentiment, but there are big logistical and political problems related to that. Just look at how weird their audio/video support is already because they wanted to make sure they're using free players, free codecs, free assets.
I realize I'm only listing problems, but it's important to think of those. From my perspective, I think it's a lot more about WikiPedia picking their battles and focusing in textual information (with tidbits of other media) rather than "never thinking about that".
Actually letting people play with the technology is an awesome thing, but I wonder if WikiPedia is the place for that.
Good thing sites like https://archive.org/details/softwarelibrary_msdos_games exist.
All in all it would help, but only with trivial snippets approaching hello-world complexity or self-contained examples better suited for tutorials rather than encyclopaedias.