Thanks for the comment! I would say that people creating roguelike definitions usually have a list of games that they feel are "roguelike", and a list of games that feel are not "not roguelike", and try to find features which match these two lists.

So, for example, all early roguelikes had character graphics, so character graphics were often put in roguelike definitions, but today we know that a game can be graphical and still feel like a roguelike, so it is given rarely (maybe except people who only know the ASCII ones and do not know how the traditional genre has evolved since then).

Early roguelikes were compared to text adventures and arcade-style games (so permadeath was nothing special), then to RPGs (making permadeath a prominent difference), then to early permadeath games (which put focus on being turn-based, rather on deemphasizing permadeath, since roguelikes were still usually played permadeath). Games which have other roguelike features but drop permadeath are still rare. Maybe Moonring (recently released) or some future game will shake things up.