Fudging rolls is not to force the players into a predetermined story, it's to not end the story.
Why would the story end? It's almost 10 years that I no longer fudge rolls, and I've never had to "end a story" following a series of bad rolls. More than 10 campaigns, probably more than 1.000 sessions, exactly 0 fudged rolls and 0 "ended" stories. You just have to be able (and willing) to decide with your players how to keep it going.
If you constantly announce the deadliness of the encounters to the players like "hehehe, you are gonna die now, hehehe", then maybe you haven't ended a story with the players dying. My players would and do die constantly if I don't make something up. They die fighting, they die by falling off cliffs without using a rope, they die from getting into sex scenes they really shouldn't, they die by ingesting strange liquids, they die by getting trapped in a burning house, they drown, etc.
You are exaggerating my words and taking them out of context. Characters die, and the story can progress with or without them. Boromir might have been an NPC, or he might have been the PC of a player who was fine with how his adventure ended.
I'm currently playing two campaigns, and a character died to bad rolls during the last session in both of them (one to an unlucky crit of a giant crocodile skeleton, the other to two very unlycky crits of a rogue). Both players wanted to keep the same character, so we found a way to make that happen:
- the first one died in an ancient ruined temple of a forgotten deity of beasts, so the remaining spirit of this deity perceived the character's strength and, assuming the aspect of a thundering bear, struck a deal with him, bringing him back to life but linking himself to his soul. Now he has resistance to electricity, but the forgotten god slightly modified his personality (making him prone to the desire of conquest and destruction) and will try to influence him further in the future;
- the group of the second character needed his help, so they asked for help in the local temple and were directed to a high priest of Lathander who lives in a secluded lodge in the wilds. The priest was already dead, but they "avenged" him concluding his sacred mission, and Lathander blessed them, bringing the character back to life in the process.
Both characters died, both players got to keep their character. Following the dice didn't end the story, but instead added new inputs and plot hooks that we may decide to develop in the future. A simple "oh, the giant crocodile skeleton doesn't hit you" and "how lucky, the rogue misses you with both attacks" would have been the easier, more boring route.