Okay, that makes sense. Given that there are only 13 Act-of-Commitment prompts, and your chance of landing on any one of them is about 1/3 (~36%, if I did the math correctly), you will only hit 4 or 5 in an average game. This would tend to encourage developing a single recurring character, but the prompts seem to encourage multiple recurring characters (because the prompts drive the characters' stories in different and sometimes mutually exclusive directions).
As a possible solution, you could encourage a step in character creation where the player outlines several already existing relationships. This would allow the player to connect the early prompts to whichever character makes most sense and give them the opportunity to develop multiple relationships.
In my current playthrough, that is what I am doing. I am also going to try to work them into whatever other prompts I roll (even if it doesn't score commitment with them).