Conflict is necessary for a good story but not sufficient. Lots of bad scripts (and I’ve written plenty) have as much conflict (and the same kind of conflict) as enthralling movies. Adding conflict to a lethargic story will probably make it better but not necessarily good. “Indiana Jones and the Kingdom of the Crystal Skull” has about as much conflict as “Raiders of the Lost Ark” (maybe more in terms of action-packed set pieces), but it’s not as involving a film.

Conflict that results from the Protagonist seeking a goal or from the Nemesis opposing the Protagonist’s goal is more involving than random mayhem, but it’s still not sufficient.

Conflict that develops as the theme unfolds (and is dependent on the theme for its impact) is, I think, in the ballpark of sufficient. The reason the stakes ramp up as the story progresses is not that the audience is getting tired, but that as the options for plot development decrease (as in the endgame in chess), the culmination of the theme (usually at the climax of a traditionally plotted story) acquires greater emotional resonance.

Theme, imo, is where stories that have enough conflict (in terms of quantity) but that don’t involve the audience fail to connect. (And this, for me, is why “Kingdom of the Crystal Skull” falls short.)