The players decide what their characters do. So the player decides what their characters care about. Even if the player writes a War and Peace length backstory about their deep connection to their family, the player is rightfully free to decide at any moment they don’t want to be inconvenienced by that strong family connection. So despite making a character for whom “family is everything” if that family ever becomes an inconvenience, the player can (and almost certainly will) decide the character simply doesn’t care enough to bother. Which is why the orphan edgelord backstory is so popular. No hooks for drama. Most players don’t want any. I’ve watched this, and things like it, play out hundreds of times over the nearly 40 years of playing and running RPGs. When it comes down to it, the only reliable stakes a DM has that the player is likely to care about is their character’s survival. If that’s the only point of leverage that consistently works, that’s where DMs go.
If we’re comparing RPGs to fiction, which they’re not, by the way, then the vast majority of players would sit out the story as they fairly consistently refuse the call to adventure. Or would simply get sidetracked and wander off on some side quest, care more about getting paid or finding gold than most characters in fiction, or lose sight of the goal and wander off. Or find the quickest, easiest, most self-aggrandizing, most self-enriching, and most boring way possible to end the story. “No thanks Gandalf, I’m not walking through Mordor to Mount Doom to drop the ring into the fire. There’s a hole in the top of the mountain and we have giant eagles. Psh. ‘Walk’. Ha. ‘Risk’. Ha. No thanks. Oh yeah, how much will you pay me for this? You’ve had too much pipeweed if you think I’m doing this for free.” The typical gamer mindset is diametrically opposed to the fiction writer’s mindset. Fiction goes for the most drama possible, whereas most gamers go for the least drama possible. That’s why most game write ups make for boring stories. Typical D&D characters are far, far closer to Spanish conquistadors slaughtering their way across the New World in search of gold than anyone you’d find in Tolkien...well, except the villains, of course.