With my recent life experiences of relationships, I believe the saying is more suited to good hearted people dying young in a spiritual, existential way. That life and people beat them down until there is nothing left for their big hearts to give. My former psychologist, despite breaking professional guidelines and falling in love with me - she did it because to her she saw the vulnerable sweet nurtured side of me (whatever is left of it, if any) that was too much to handle. She wanted absolutely nothing more than to see me and her patients happy. Too caring, too giving, too loving. Just had a utopia vision of wanting the best for everyone by any means. But because of the complicated dynamic between us and her creating a friend out of another patient for the same reasons, she had been exposed and most of her life is ruined. She (existentially) died young and probably learned having a big heart kills you sooner.
Same happen to a former friend. Absolute angel that would test atheists but I screwed him over with repeated traumas of depression and suicidality. Now he's taken the lesson and keeps himself on guard and gives his heart in smaller doses while protecting himself. Then me. Getting screwed over by an act of God or everyone around me everytime I show a glimmer of happiness or joy or actively improving my life. Being boxed doing what I've been doing all my life because anything else and I get screwed over, dispiriting me. Demoralise until I'm a shell of my former self that everyone keeps praising me for allegedly being a great person for whatever reasons.
Maybe it gets to the point where I literally die young, hopefully soon. I'm broken down to the point of becoming hateful, bitter, jaded, cynical and hopeless that the more I'm around - the worse off everyone else is. The good die young, I guess. That's my interpretation of it.