Was the sad ending really necessary?

I don't think that Lightfoot himself knew how badly he was hurt. He had always got along on his charm and glibness; he had probably taken a few beatings from angry partners in crime, in his days - but Red was something else, entirely.

Watch Red; from the first time you see him, you can just feel his entire body wound up like a steel spring, waiting to unleash on somebody at the first opportunity.

After Red's kicking, Lightfoot probably thought that it had just been a really savage beating; he didn't stop to think whether there was any real internal damage done. And he seemed to be operating okay when he and Thunderbolt found the money behind the schoolhouse wall. I reckon he was getting internal messages, such as "I feel sick," but they were coming up against other internal messages like "I've been beat up, before," and "Look at all that money!"

I don't think he would have known enough to ask Thunderbolt to take him to professional medical attention.

- Oh, SOMEbody asides me is gonna RUE this here particular day...

Its been a long time since ive seen this film, and my newly ordered blu ray has yet to arrive, but im guessing he died from "intracranial hemmorhage" his speech became increasingly slurred and his eyes lost "direction" ... Jeff Bridges is a great actor!

He died from, as others have mentioned, from a closed head injury, probably a blood clot that as it grew, put pressure on his brain causing his speech and mobility issues. He probably realized it how bad it was too late, and the clot ruptured killing him almost instantly.

Something else, and this is just my opinion, I was talking with a friend not long ago about this movie and other movies of the time, and I came to a conclusion about them saying that "The hero's in the movies were not always the good guys, and sometimes the hero's die in the end". Look at Butch Cassidy and the Sundance Kid, they were the hero's in the movie, Dirty Mary/Crazy Larry, Vanishing Point, Race With The Devil, Easy Rider, to name a few.

1 Baker 11, in pursuit of 1973 yellow Mustang license number 614 Henry Sam Ocean

It was the 70s. If it came out in the 80s you'd have gotten a bullshit cheery ending.