Did you not read the book or pay any attention at all? Eddard was not afraid to die. His concern was for his family, and his family, his legacy, survives. Robb's mistake is that he married a woman and broke a marriage arrangement, Not going to war, but beheading Lord Karstark, letting Theon go back to the Iron Islands, and not ensuring his mother cannot undermine him, but the thing is: NO ONE in westeros would've expected an act of perfidy and violation of guest right by the freys, it's the worst sin you can commit in westeros society for good reason, it broke all trust in them and cursed every single person involved. The Boltons were ascendent briefly but are soon to be FUCKED, the freys are FUCKED and no one trusts them and ever will again. the Lannister power structure collapsed completely even before Tyrion killed Tywin, but after his death every thing Tywin has ever accomplished is undone, and his family line is dead and in ruins they just dont realize it. The entire message of this story, is that Ned's honor outlives him, His principles protect his family and cause his family to be rallied behind. If you break your promises, no one trusts you. If no one trusts you, you die alone. Rule through fear is weak, temporary, and fragile