To support this hypothesis, you'd have to show that some other process did make (for example) the perfect editor.
Otherwise, this is not a weakness of open source.
I wouldn't say they make the perfect editor, but they do make changes.
For example, I like the fact that almost every editor on my mac obeys the standard shortcut keys (at the minimum, apple+x,c,v for cut/copy/paste, apple+z undo, apple+s save, apple+q quit, apple+f find, apple+g find next, apple+a select all).
If you started vim or emacs today, would you choose on a mac to not follow the standard interface rules, when the editor was first started? I would (personally) hope not.
No, it uses the keys I listed, like everything else on the mac (I feel like you are aiming at something here, or are you just curious about mac terminals?)
* Well, not all of them, save doesn't really make sense for a terminal, and 'cut' can't really be implemented for a general terminal app. but copy/paste/find/find next/close window/select all and others are all fine).
