Slytherins by definition lack necessary bravery to keep getting into all fights that maintaining a position within feudal system requires.
As long as acquiring power requires personally charging into an enemy army, Gryffindors will hold most of it. Fellow Gryffindors will be easily impressed by someone who does so without a second thought. Slytherins won't last long. To someone who actually values their life and comfort like all Slytherins do, this is very expensive kind of signaling.
I don't agree on this one. Slytherins will do what they need to do to get power. There is also quite a difference between creating, maintaining and enforcing an image of personal bravery and being personally brave. Those who maintain the greatest image of personal bravery will be those that are best at choosing to personally engage in the elements of a battle that pose little risk to themselves and who proficient at arranging the demise of anyone who doubts their courage. It isn't hard to choose the bravest rivals and ensure they are put in the most danger...
Update: This post has also been superseded - new comments belong in the latest thread.
The second thread has now also exceeded 500 comments, so after 42 chapters of MoR it's time for a new thread.
From the first thread: